======================RADIO_TV==================================== ======================RADIO_FREQUENCY======================================= ------------------------------------------------------------- 535-1635 KHz AM 44-49 Mhz Analog cordless phone 54-88 Mhz TV chaneel 2-6 (VHF) 88-108 MHz FM 174-216 Mhz TV channel 7-13MHz (VHF) 470-806 MHz TV Channel 14-69 (UHF) 800 MHz RF wireless modems 806-890 MHz Cellular Phones 900 MHz digital cordless phones 900-929 Mhz Personal Communication services (PCS) 929-932 Mhz Nation wide pagers 932-940 MHz two-way pagers 1610-1626.25 MHz Satellite phones uplink 1850-2200 MHz Future PCS 2483.5-2500 MHz Satellite phones downink 4-6 Ghz Satellite TV large dish 11.7-12.7 Ghz Satellite TV small dish 28-29 GHz Wireless "cable" TV ------------------------------------------------------------- Frequency SPECTRUM 0 Hertz Steady direct current 50-60 Hetz AC power ----------------------USA--------------------------------- 16-16.000 kHz Audio frequencies 5000Km 10-30 kHz v.l.f -very low frequency 30-10Km 30 kHz - 30 MHz Radio Frequencies 30-300 kHz l.f. low frequency 10-1Km 30S35 kHz Marine com & navigation, aero nav. 300-3000 kHz m.f medium frequencies 1000-100m 535-1605 kHz AM broadcast bands 1800-2000 kHz 60 meter band ----------------------Football_Field--------------------------- 3-30 MHz h.f. - high frequencies 100-10m 3.5-4 MHz 80 me1erband 7-7.3 MHz 40 band 14-14.35 Mnl 20 meter band 21-21.45 MHz 15meterbend 26.85-27.54 MHz Industrial, Scientific, medical 28-29.7 MHz 10 meterband 26.86-27.455 MHz Citizens Band Class D ----------------------Human----------------------------------- 30-300 MHz very high frequencies 1O-1m 30-50 MHz Police,fire,highway,railroad 50-54 MHz 6 meter band 54-72 MHz TV channels 2 to 4 72-76 MHz Government, Aero,Marker 75MHz 76-88 MHz TV channels 5 and 6 88-108 MHz FM broadcast band 108-118 MHz Aeronautical navigation 118-136 MHz Civil Communication Band 148-174 MHz Government 144-148 MHz 2 meter band 174-216 MHz TV channels 7 to 13 216-470 MHz Amateur, government. CB Bend non-govemment, fixed or mobile aeronautical navigation 220-225 MHz Amateur band. 1-1/4 meter 225-400 MHz Military 420-450 MHZ Amateur band, 0.7 meter 462.5-465 MHz Citizens Band 300-3000 MHz u.h.f. - ultra high frequencies lOO-1Ocm 470-890 MHz TV channels 14 to 83 890-3000 MHz Aero navigation, amateur bands. Qovernment& non-government, fixed and mobile 1300-1600 MHz Radar band 3000-30,000 MHz s.h.f. - super high frequencies 10-1cm Government and non-govetnment, amateur bands, radio navigation ----------------------Grain_OF_SAND------------------------------- 30 to 300 GHz Extra-high frequencies (weather radar, experimental, government) 1-0.1cm ----------------------Bacterium------------------------------- 30-0.7um Infrared light and heat 0.76-0.39 um Visiblelight 300teraHz 6470-7000 angstroms Red light 5850-6740 angstroms Orange light 5750 5850 angstroms Yellow light 5560-5750 angstroms Maximum visibility 4912-5560 angstroms Green light 4240-4912 angstroms Blue light 4000-4240 angstroms Violet light ----------------------Virus------------------------------- 0.390-0.032um Ultraviolet light 30petaHz 3200-1 angstroms X-rays 1-0.06 angstroms Gamma rays ----------------------Atom------------------------------- 0.0005 angstroms Cosmic rays ----------------------Atomic_Nucleus------------------------------- 1um micrometer(10^-6m) GHz gigahertz(10^9 Hz) angstrom 10^-10 meters ------------------------------------------------------------- Long wave below 550Khz 510 -535 Misc Radio beacons 500 KHz Distress(CW) ship to shore 415-490KHz Maritime mobile (CW) ship to shore 285-400KHz Radio beacons,weather weath,AM, carrierCurrent_60Hz_trans aeronautical and marine 190-285KHz Radio beacons,weather weath,AM, carrierCurrent_60Hz_trans european long wave broadca 160-190KHz Fixed Public,license-free exper 1W , no need licen experiimental european long wave broadcast fixed(point to point) 110-160KHz maritime mobile, noisy, some RTTY trans lowest freq long wave broadcast fixed(point to point) 90-110KHz Loran Navigation 30-90KHz fixed,mobile RTTY trans, some CW , noisy standard freq /time sign 14-30KHz submarine comunications RTTY trans, some CW , noisy VLF wold wide hig-power miltary and commercial 10-14KHz atm phenomena, whistlers lowest radio sprect freq used omega signals freq standard below 10KHz atmoshper noise whistlers experimental experiment trans miltary ------------------------------------------------------------- AM radio: 535 kilohertz to 1.7 megahertz Short wave radio: 5.9 megahertz to 26.1 megahertz Citizens Band (CB) 26.96 megahertz to 27.41 megahertz Television stations 54-88 megahertz for channels 2-6 FM radio 88 megahertz to 108 megahertz Television stations 174-220 megahertz for channels 7-13 Garage door openers around 40 megahertz alarm systems around 40 megahertz cordless phones: Bands from 40 to 50 megahertz Baby monitors: 49 megahertz RC airplanes: around 72 megahertz, which is different from... RC cars: around 75 megahertz Wildlife tracking collars: 215 to 220 megahertz MIR space station: 145 megahertz and 437 megahertz Cell phones: 824 to 849 megahertz 900MHzcordlessphones Obviously around 900 megahertz! scanner cannot listen Air Traffic Control radar: 960 to 1,215 megahertz GPS Global Positioning System: 1,227 and 1,575 megahertz Deep space radio communications: 2290 megahertz to 2300 megahertz aviation band 118 MHz to 135.975 MHz pilot-to-pilot 123.45 MHz into your scanner will let you hear some police/municipality frequencies in the 800 MHz range. most scanners 29-512 megahertz MHz) range. car race 460 to 470 MHz ------------------------------------------------------------- Cathode Ray Tube "cathode" is a heated filament like light bulb filament. vacuum inside a glass "tube. "ray" isa stream of electrons that naturally pour off a heated cathode into vacuum. anode is positive,attracts electrons off of cathode. electrons is focused by focusing anode into a tight beam and then accelerated by an accelerating anode. hits flat screen at the other end of tube. screen is coated with phosphor, which glows when struck steering coils are simply copper windings create magnetic fields inside the tube, One set of coils moves the electron beam vertically, another set moves the beam horizontally. black-and-white TV, screen is coated with white phosphor move electron beam in a "raster scan" pattern across and down the screen. one line across the screen from left to right. I then quickly flies back to the left side, All TVs use interlacing technique when painting screen. screen is painted 60 times per second but only half lines are painted per frame. beam paints every other line as it moves down the screen, example every odd-numbered line. next time it it paints even-numbered lines, entire screen, two passes, painted 30 times per second. alternative to interlacing called progressive scanning, which paints every line on screen 60 times a second. Most computer monitors use progressive scanning because it significantly reduces flicker. Because electron beam is painting all 525 lines 30 times per second,paints 15,750 lines per second. (Some people can actually hear this frequency The horizontal retrace signals are five microsecond pulses at zero volts. signal varying wave between 0.5 volts and 2.0 volts, 0.5 volts representing black, 2 volts representing white. This signal drives intensity circuit for the electron beam. In a black-and-whiteTV this signal can consume about 3.5 MHz of bandwidth, while in a color set the limit is about 3.0 MHz. A vertical retrace pulse is similar to a horizontal retrace pulse but is 400 to 500 microseconds long. vertical retrace pulse is serrated with horizontal retrace pulses in order to keep the horizontal retrace circuit in the TV synchronized. color TV signal starts off like a black-and-white signal. extra chrominance signal is superimposing a 3.579545 MHz sine wave onto the standard black-and-white signal. Right after horizontal sync pulse, eight cycles of a 3.579545 MHz sine wave are added as a color burst. Following eight cycles, phase shift in chrominance signal indicates color to display amplitude of signal determines saturation.following table shows you the relationship between color and phase: Color Phase Burst 0 degrees Yellow 15 degrees Red 75 degrees Magenta 135 degrees Blue 195 degrees Cyan 255 degrees Green 315 degrees standard NTSC analog waveforms requires 4 MHz bandwidth. add in sound,something called vestigial sideband and a little buffer space, TV signal requires 6 MHz bandwidth. FCC allocated three bands of frequencies in radio spectrum chopped into 6 MHz slices to accommodate TV channels: 54 to 88 MHz for channels 2 to 6 174 to 216 MHz for channels 7 through 13 470 to 890 MHz for UHF channels 14 through 83 composite TV signal described in the previous sections can be broadcast to your house on any available channel. composite video signal is amplitude modulated into appropriate frequency, and then the sound is frequency modulated (+/- 25 KHz) as a separate signal, ------------------------------------------------------------- typical VGA pinout: pin 1 - Red video pin 2 - Green video pin 3 - Blue video pin 4 - Ground pin 5 - Self test pin 6 - Red ground pin 7 - Green ground pin 8 - Blue ground pin 9 - No pin pin 10 - Digital ground pin 11 - Reserved pin 12 - Reserved pin 13 - Horizontal sync pin 14 - Vertical sync pin 15 - Reserved ------------------------------------------------------------- PAL and NTSC timing information Horizonal Timing PAL NTSC A (us) 64 B (us) 4.7+-0.2 4.7+-0.1 C (us) ? 1.4 D (us) 52 E (us) 12 Horiz. Frequency (Hz) 15625 15734.2 Subcarr. frequency (MHz) 4.43 3.579545 Subcarr. cycles per line ? 227.5 XXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXX_ _W__XXXXXXXXXXXXXXXXXXXXXX_ _W_XXXXX |_| VIDEO |_| |B| |---------D----------|C| |----E---| |--------------A--------------| Vertical Timing PAL Vertical frequency(Hz) 50 59.94 Blanking (lines) 25-37 Active lines 482-486 Total lines 625 525 Equalization pulses 3+3+3 O (scanlines) 312.5 262.5 P (ms) Q (ms) R (scanlines) 241-243 S (ms) XXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXX_ ___XXXXXXXXXXXXXXXXXXXXXX_ __XXXXX |_| VIDEO |_| |P|-Q-|---------R----------|S| |---T--| |--------------O-------------| Horizonal Timing PAL NTSC A (us) 64 B (us) 4.7+-0.2 4.7+-0.1 C (us) ? 1.4 D (us) 52 E (us) 12 Horiz. Frequency (Hz) 15625 15734.2 Subcarr. frequency (MHz) 4.43 3.579545 Subcarr. cycles per line ? 227.5 XXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXX_ _W__XXXXXXXXXXXXXXXXXXXXXX_ _W_XXXXX |_| VIDEO |_| |B| |---------D----------|C| |----E---| |--------------A--------------| Vertical Timing PAL Vertical frequency(Hz) 50 59.94 Blanking (lines) 25-37 Active lines 482-486 Total lines 625 525 Equalization pulses 3+3+3 O (scanlines) 312.5 262.5 P (ms) Q (ms) R (scanlines) 241-243 S (ms) XXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXX_ ___XXXXXXXXXXXXXXXXXXXXXX_ __XXXXX |_| VIDEO |_| |P|-Q-|---------R----------|S| |---T--| |--------------O-------------| Published by ELH Communications Ltd. all rights reserved. Circuits [ index ][ back ][ site search ] [ acronyms ] [ discussion ] [ mail to a friend ] [ post message ] PAL and NTSC timing information Horizonal Timing PAL NTSC A (us) 64 B (us) 4.7+-0.2 4.7+-0.1 C (us) ? 1.4 D (us) 52 E (us) 12 Horiz. Frequency (Hz) 15625 15734.2 Subcarr. frequency (MHz) 4.43 3.579545 Subcarr. cycles per line ? 227.5 XXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXX_ _W__XXXXXXXXXXXXXXXXXXXXXX_ _W_XXXXX |_| VIDEO |_| |B| |---------D----------|C| |----E---| |--------------A--------------| Vertical Timing PAL Vertical frequency(Hz) 50 59.94 Blanking (lines) 25-37 Active lines 482-486 Total lines 625 525 Equalization pulses 3+3+3 O (scanlines) 312.5 262.5 P (ms) Q (ms) R (scanlines) 241-243 S (ms) XXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXX_ ___XXXXXXXXXXXXXXXXXXXXXX_ __XXXXX |_| VIDEO |_| |P|-Q-|---------R----------|S| |---T--| |--------------O-------------| ------------------------------------------------------------- Video signal levels Video signals used in TV production For all standard TV video signal systems the standard video level was 1 V p-p in 75 ohms, for video + sync. However, waveform monitors were marked in 140 "IRE units", 40 for sync, and 100 for video. Under the original RS-170 standard, video was 1.4 Vp-p, with the white level 1.0V up from blank (which is the reference) and the sync tip 0.4V down (negative) with respect to the same reference level. And from blank to white was 100 IRE units. The RS-170 levels have pretty much been replaced in most applications by the later RS-343 standard levels. Under this standard, the entire signal (including the sync pulses) was reduced to 1.0 Vp-p across 75 ohms. However, the same 100/40 division above and below the blank level was retained. This results in the reference white level being 0.714 V positive from blank, and the sync tips 0.286 V negative from blank. The BLACK level, under this standard, is slightly up from blank, having an 0.054V "setup" or "pedestal". Standard practice in Europe has also been to use a 1.0V p-p signal, but they simplified life and set white to +0.700V and sync to -0.300V, again with respect to the blanking level, and did away with "setup" (i.e., black and blank are the same level). PC video levels From European 1 Vpp system we got one common PC video standard, which uses 0.700V p-p video (with separate syncs). Unfortunately, we also saw the development of ANOTHER common PC video practice, which was to simply use RS-343 with the setup chopped out - resulting in 0.660V p-p for the video. Compatability issues All of these are close enough to work about equally well on most equipment and monitors, but there are several "standards" for video floating around. ePanorama.net - Ground Loops ------------------------------------------------------------- S-video to composite video adapter convert Y/C video (S-video) to composite video. works with both PAL and NTSC video standards. Y-ground------------------+ +---------- RCA/composite ground C-ground------------------+ Y-------------------------+ +--------- RCA/composite video C------------||-----------+ 470pF circuit can be quite easily build inside a S-video connector case if a physically small size 470 pF (ceramic) capacitor is used.Larger capacitor values also work, but cause picture to become"softer". voltage rating of capacitor can be 10V or more. This circuit works in practice quite well even though circuit operation is not ideal. impedances and signal levels not matched exactly right, but near enough to work accetably. picture quality you get from this circuit is is good, but not as good as with best possible composite video output circuitry. Here is pinout of S-video connector shown from end with FEMALE PINS (picture is a view on equipment back/front panel): 1 Y ground 2 C ground 3 Y (luminance+sync) 4 C (crominance) 7-pin S-video What if my PC graphics card has 7-pin S-video connector four pin S-video connector as shown above is standard connector for carrying S-video. Those seven pin connectors seen on some PC graphics cards are non-standard connectors for carrying S-video. use of pins on those seven pin connectors is not standardized and can vary from manufacturer Generally four pins on those 7-pin connectors on same places as standard four pin S-video connector other three pins can have then some extra signals not part of S-video (usually some pins of those carry composite video and some control signals, in opposite way have a composite video signal want to feed to S-video circuit sort of work also in this way. If you connect a comoisute video source to S-video input of your TV using this circuit, picture quality will be worse than if using real composite vidoe input of your TV. reason for this is that after circuit color information is still in brighness signal, see some interference on screen caused by color subcarrier which gets to screen. Closed-Caption Decoder http://www.southernnetcom/auditech Since 1993, television sets with screens of 13 inches or more that are sold in the United States must have built-in decoders,under Television Decoder Circuitry Act. Set-top decoders are available, too, for older TV sets. captions hidden in line 21 data area found in vertical blanking interval of television signal. Line 21 is the line in the vertical blanking interval that has been assigned to captioning (as well as time and V-chip information). Each frame video transmit two characters of captioning (or special commands that control color, popups, etc.) VCR Plus Decoded http://www.tinaja.coml third /vcrplus.pdf ------------------------------------------------------------- copy-protected VHS tapes - TOSHIBA case of making them sensative to adapt to varying TV conditions city is likely to get a stronger signal than > on in a remote mountain village. why AGC's were introduced. it made macrovision possible as it could fool AGC. 1. RF-AGC which compensates for different signal strength at aerial, it measures RF amplitude and is *not* sensitive to video contents because with negative modulation the sync is the peak and isconstant, this AGC will not work on CVBS (baseband video) inputs. 2. Video-AGC which normalizes baseband signals which enter *after* tuner-IF. A.o. this compensates for different signal strengths when you connect two VCRs together. It measures peak-white, so it *is* sensitive to video content and thus to Macrovision pulses. a television does NOT have a video-AGC, unless you want to call beam current limiter circuits an AGC. (Exception: the Secam-L system with positive modulation requires an RF-AGC which measures peak-white instead of peak-sync.) > Same reason some TV's are susceptable, as the AGC in the amplifier stage > gets misled and boosts or cuts the signal accordingly. No, the RF-AGC does not see the peak-white of the anti-copy pulses. If you connect the VCR to the TV via the CVBS (baseband) input, then the RF-AGC is not even in the path. Still, it may be disturbed. But the sync separator may see the extra inserted Hsync pulses, and due to the phase disturbance the video clamping may be disturbed too. Hope I've cleared this up a little more. (Did I ???) Have had some sleepless nights over Macrovision too ... Original Subject: Re: Synchronous Detection In article , rtorgerson@electriciti.com' says... > >I have a application were I am sending out a test signal and I receive back a >response that is 2 to 100f the signal that is sent out. The common mode >noise can be ten times my test signal. If common-mode noise is the only problem, why don't you make life simple for yourself and use balanced transmission. Works great for IEEE 10base-t (10 MBPS ethernet on twisted pair). >The one problem I have is that I want to >set the test signal as large as I can without distortion. The way I was going >to do this was by measuring both the fundamental and the second harmonic. When >the second harmonic is 50f the fundamental I would reduce the test signal. This is confusing. Why can't you just measure the harmonic distortion vs. output power, and then set the transmitting device at a reasonable level? Or is your load generating harmonics that depend on the TX level? >Does any one know of any good references for Synchronous Detection? And is >it possible to measure both the fundamental and a second harmonic with Synchronous >Detection? The advantage of synchronous detection is that it's a linear process and can minimize the receiving bandwidth. You can achieve it by either transmitting a pilot tone with your signal, or recovering a synchronous reference by some form of phase locked loop operating on the received signal. If your signal has very narrow bandwidth but with long term frequency drift, synchronous detection will permit you to use a very narrow recovery bandwidth. A phaselocked loop is in fact a synchronous detector. An example of effective synchronous detection is the 3.58 MHz color burst subcarrier loop in a TV set. It's locked to the master oscillator at the station to give you a perfect color rendition of Roseanne's face. -- ------------------------------------------------------------- no channel 1 ? on broadcast TV? ONCE UPON A time, there was one. After World War II, great demand for broadcast locations on the electromagnetic spectrum. Federal Communications Commission re-evaluated in 1945. allocated 44- to 216MHz VHF channels 1 through 13. this move, VHF television took 72- to 76MHz range previously allocated for nongovernmental land and mobile use In 1948, the FCC reallocate beginning of VHF space (44- to 50MHz) to nongovernmental land and mobile use, compensating for the bandwidth lost earlier. was the space that channel 1 occupied. Rather than recalibrate FCC simply deleted channel 1. ------------------------------------------------------------- exp(j*X) cos(x) +j*sin(x) ------------------------------------------------------------- Maxwell's Equations __ \/ dot J = -delta_p/dt __ \/ cross E = -delta_B/dt V=delta_Phi/dt __ \/ cross H = J+ delta_D/dt H =I*N __ \/ dot D = p __ \/ dot B = 0 ------------------------------------------------------------- <---------One line of NTSC-standard color video----> 1.54us 750ns |\ /\ < > < > /|/ \/\/\/|/ \/\/|/|_/\/\|\/\/\ _ __||||_/\/ \__ | | | |||| : | |____| ^ |__COLOR BURST 3.579545MHZ <-------> 4.85us <---> 4.71us <---------------> Horizontal blanking 11.1us <----52.4us video information-....---> 100 IRE 1V................................ White 1.00V |\ /\ /|/ \/\/\/|/ \/\/ 0 IRE 0.3V.._ _|||_/\/ \__black0.25v | | | ||| -40 IRE 0V | |__| sync0.00v <-----------63.5us video information-....----> TV <------H------------> _ _ Horzontial _| |_;;_ _| |_;;_ 15734.25Hz=2/455 chroma | < > | _.... _| <----->| chroma=3,579,545Hz | .075H |_/\/ \/ .13H |_ +/-10Hz _| FIG. 2„A TYPICAL NTSC HORIZONTAL scan line. The blanking interval between lines gives the electron beam time to reset. Over time, a lot of additional information has been placed in the blanking interval. 100 IRE 1V............................................ |\ /\ /|/ \/\/|/ \/\/|/|_/\|\/\ 0 IRE 0.3V.._ __|||_/\/ \__ | | | ||| -40 IRE 0V | |___| <--control-> <--52.4us video information-.--> CONTROL AREA. NTSC video standard signal range 0 to 1 volt pk-to-pk. *** TV <------H---------> _ _ Horzontial _| |_;;_ _| |_;;_ 15734.25Hz =2/455 chroma | < > | .. __| <----->| chroma =3,579,545Hz | .075H |_/\/ \/ .13H |_ +/-10Hz _| Horz = 15734.24 =2/455 times Chroma Vert =59.94Hz =2/52H Horz blank =.18 H Vert blank = 21H ____ LLL|||||LLLLL_|_|_|_| |<-><---><---><----->| |\|\| 3H 8H 8H 12H |_ Vertical =59.594Hz = 2/525 30 frames/sec x y Video 45.76MHz | / R .67 .33 Sound 41.25MHz | / G .21 .71 | / B .14 .08 | / |/____ Color Vector sound press level =SPL=20logP/.0002 P measured in bars 1 bar = 1ATM I=P^2/p*c I=sound intensity p,c=density,speed of sound in air .0002ubars= Iref(0dB)= 1E-16 watts/cm2 <-------One line of NTSC-standard color video---> |\ /\ /|/ \/\/\/|/ \/\/|/|_//\ _ __||||_/\/ \__ | | | |||| : | |____| ^ |__COLOR BURST 3.579545MHZ < > 750ns breezeway <-------> 4.85us Back porch <---> 4.71us Horz Sync < > 1.54 front porch <---------------> Horizontal blanking 11.1us <--52.4us video information-...--> ------------------------------------------------------------- TIME-BASE CORRECTOR In VRC takes the incoming video signal, strips sync from it, remixes it with a new set of sync signals. line by line, and the original sync is just used as a trigger to mark the correct position on the line for injecting the new syn ------------------------------------------------------------- MP3 files CD stores music using 44,100 samples per second, 16 bits per sample and two channels 10 million bytes of data per minute of music three minute song requires 30 megabytes of data. MPEG acronym for Moving Picture Experts Group. developed compression systems used DVD movies, HDTV broadcasts and DSS satellite systems use MPEG compression includes a subsystem to compress sound, called MPEG audio Layer-3. abreviation - MP3. MP3 compress a song by a factor of 10 or 12 retain CD ======================PROTOCOLS_CD=========================== 74 minutes chosen as the standard length? general belief is that it was chosen because the CD designers wanted to have a format that could hold Beethoven's ninth symphony. They were trying to figure out what diameter to use, and the length of certain performances settled it. BURN-Proof (or BurnProof) unfortunate abbreviation of "Buffer-Under-Run Proof". T he technology allows you to avoid buffer underruns by suspending and restarting the write process when the recorder's buffer is about to empty. common sampling rate of 44.1KHz was derived for both NTSC and PAL formats sampling rate for "professional" audio, 48KHz, was chosen because it's an easy multiple of frequencies used for other common formats, e.g. 8KHz for telephones. fairly difficult to do a good conversion from 48KHz to 44.1KHz, which makes it There is relatively little difference in audible quality between 44.1KHz and 48KHz, since the slight increase in frequency response is outside the range of human hearing. Some inaudible tones produce "beats" with audible tones and thus have a noticeable impact, but the improvement from 44.1 to 48 is marginal at best. DD-R and DD-RW Sony standards "double-density" recordable and rewritable discs. The discs hold 1.3GB of data, and are relatively inexpensive,but aren't compatible with CD or DVD players. can only read the discs in a DD-R/DD-RW drive. Andrew S. Tanenbaum "The nice thing about standards is that you have so many to choose from." bootable CD-ROM? On a Mac, CD bootable if a bootable system folder on it. Tell the recording software that you want to make the CD bootable; this usually involves clicking in a checkbox before burning the first session. Then, copy a bootable system folder onto the disc. An easy way to create an appropriate system folder is to launch the system installer, tell it you want to do a "Custom" install, choose the "Universal System" option, and then install it onto the CD source volume. One caveat: any control panels or extensions that want to write to their preferences files will fail. You may need to write from a system folder that has been booted at least once. make a CD without that two-second gap between tracks? Most CD recorders are capable of doing this, given the right software. The key is to use disc-at-once recording instead of track-at-once. Most CD players can only handle uncompressed audio in "Red Book" format. Some newer player, can play MP3 files from a CD-ROM. Such discs should be written in ISO-9660 with 8+3 filenames, ought to use 128Kbps and "plain" stereo for broadest compatibility. (http://www.ijamworld.com/) recommends putting no more than 50 MP3 files in a directory. MP3 is a "lossy" compression format, meaning that it gets its exceptional compression ratios by throwing some of the data away. (MP3 can get a 10:1 reduction with hardly any degradation in audible quality; RTFM (Read The Fine Manual) CD recording process can't be interrupted in mid-session. Once the laser starts writing, recorder must always have data to write, makers of CD recorders put write buffer in drive, usually between 512K and 4MB in size. Data read from the hard drive, tape, or another CD is stored in the buffer, and pulled out as needed by the recorder. If recorder requests data from the write buffer, but there's none there, it's called a buffer underrun. disc is still spinning, but there's no data to write, so the recording process aborts. preventing buffer underruns Use a fast, AV-friendly hard drive Record at a slow speed - 1x. Don't do anything else with the computer while recording. Also watch out for things like anti-virus programs that wake up, virtual memory settings that cause swapping, screen savers that activate during the CD creation process, unusual network activity, and background downloads of data or faxes. Seven Rules of Successful CD Recording" 1.Defragment Your Disk 2.Use a Partition for Staging Input 3.Create a Real Image 4.Test before writing 5.Stabilize Your System for CD-R 6.Shut Down Other Applications 7.After the Burn: Label and Test Write process keeps failing N minutes in speed set to 1x. getting worse over time, may just need to defragment your hard drive. basic building blocks of CD-R media cyanine dye cyan blue in color, phthalocyanine dye faint aqua tinge, metalized azo dark blue. reflective layer is either a silvery alloy, exact composition of which is proprietary, or 24K gold. Taiyo Yuden produced the original gold/green CDs, which were used during the development of CD-R standards.Mitsui Toatsu Chemicals invented the process for gold/gold CDs. Mitsubishi developed the metalized azo dye. Silver/blue CD-Rs, manufactured with a process patented by Verbatim, first became widely available in 1996. According to the Ricoh web site, the silver/silver "Platinum" discs, based on "advanced phthalocyanine dye", were introduced by them in 1997. They didn't really appear on the market until mid-1998 though. The top (label) side of the CD is the part to be most concerned about, since that's where the data lives, and it's easy to damage on a CD-R. Applying a full circular CD label will help prevent scratches. CD-Rs CD-RWs last? manufacturers claim 75 yrs (cyanine dye, in "green"discs), 100 years (phthalocyanine dye, used in "gold" discs), or even 200 years("advanced" phthalocyanine dye, used in "platinum" discs) once the disc has been written. shelf life of an unrecorded disc has been estimated at between 5 and 10 years. excessive heat, humidity, or to direct sunlight greatly reduce lifetime. easiest way to make CD-R unusable is to scratch the top surface. Keep them in a cool, dark, dry place, they will probably live longer than you do By some estimates, pressed CD-ROMs may only last for 10 to 25 years, because aluminum reflective layer starts to corrode after a while. 74 minutes == 333,000 sectors == 650.3MB CD-ROM == 746.9MB CD-DA 80 minutes == 360,000 sectors == 703.1MB CD-ROM == 807.4MB CD-DA Whatever you do, don't try to peel a label off once it's on. You will almost certainly pull part of the recording layer off with the label. CD-R for "CD-Recordable". are WORM (Write Once, Read Multiple) CDs you buy in a store are pressed from a mold. CD-Rs are burned with a laser. less tolerant of extreme temperatures and sunlight, more susceptible to physical damage. CD-Rs or pressed CDs last longer difficult to answer. About 74 minutes of audio, or about 650MB of data. DVD, try http://www.dvddemystified.com/dvdfaq.html. "Write-once media is manufactured similarly to conventional playback-only discs. As with CDs, employ a polycarbonate substrate, reflective layer, and a protective top layer. Sandwiched between the substrate and reflective layer, is a recording layer composed of an organic dye. .... Unlike regular CDs, a pre-grooved spiral track is used to guide the recording laser along the spiral track; greatly simplifies recorder hardware design and ensures disc compatibility." basic CD-R is layered like this, from top to bottom: [optional] label [optional] scratch-resistant and/or printable coating UV-cured lacquer Reflective layer (24K gold or a silver-colored alloy) Organic polymer dye Polycarbonate substrate (the clear plastic part) real gold in "green" and "gold" CDs, but if you hold to it's thin enough to see through gold layer is between 50 and 100nm thick). data is closest to the label side of the CD, not the clear plastic side that the data is read from. If the CD-R doesn't have a hard top coating such as Kodak's "Infoguard", it's fairly easy to scratch the top surface and render the CD-R unusable. A pressed CD has raised and lowered areas, referred to as "lands" and "pits", respectively. A laser in the CD recorder creates marks in the disc's dye layer that have the same reflective properties. The pattern of pits and lands on the disc encodes the information and allows it to be retrieved on an audio or computer CD player. Discs are written from the inside of the disc outward. On a CD-R you can verify this by looking at the disc after you've written to it. The spiral track makes 22,188 revolutions around the CD, with roughly 600 track revolutions per millimeter as you move outward. If you "unwound" the spiral, it would be about 3.5 miles long. The construction of a CD-RW is different: [optional] label [optional] scratch-resistant and/or printable coating UV-cured lacquer Reflective layer Upper dielectric layer Recording layer (the part that changes form) Lower dielectric layer Polycarbonate substrate (the clear plastic part) See the net references section for pointers to more data (especially http://www.cd-info.com/). You can find some nice drawings at http://www.nswc.navy.mil/cosip/nov97/cots1197-2.shtml and http://www.pctechguide.com/09cdr-rw.htm. ------------------------------------------------------------- CD-ROM copy protection work? A simple and commonly seen technique is to increase length of files on CD so appear to be hundreds of megabytes long.by setting file length in disc image to be much larger than it really is. One possible implementation, given sufficient control over reader and mastering software, is to write faulty data into ECC portion of a data sector. Standard CD-ROM hardware will automatically correct "errors", writing different set of data onto target disc. reader then loads the entire sector as raw data, without doing error correction. If it can't find the original uncorrected data, it knows that it's reading a "corrected" duplicate. This is really only viable on systems like game consoles, where the drive mechanism and firmware are well defined. A less sophisticated but nonetheless effective method is to press a silver CD with data out beyond where a 74-minute CD can write. Copying the disc would then require special CD-R blanks, moving data and hacking the disc to compensate, or pressing silver discs with the pirated data. If taken too far, though, the disc can become unreadable on some drives. An overburned 80-minute blank (sections (3-8-1) and (3-8-3)) can hold about as much as you can reliably fit on a disc anyway. The approach PC software houses have taken lately is to use nonstandard gaps between audio tracks and leave index marks in unexpected places. discs are uncopyable by most software, and it may be impossible to duplicate them on drives that don't support disc-at-once recording Another method gaining popularity is non-standard discs with a track shorter than 4 seconds. Most recording software, and in fact some recorders, will either refuse to copy a disc with such a track, or will attempt to do so and fail. A protected application would check for the presence and size of the track in question. Some recorders may succeed, however, so this isn't foolproof. (In one case, a recorder could write tracks that were slightly over three seconds, but refused to write tracks that were only one second. There may be a limit below which no recorder will write. When you put a data CD into your CD-ROM drive, the OS finds the last closed session on the disc and reads the directory from it. (Well, that's how it's supposed to work. Depending on your operating system and CD-ROM drive, you may get different results.) If CD is ISO-9660 format - which it almost certainly is unless it's a Macintosh CD written in HFS - the directory entries can point at any file on the CD, no matter which session it was written in. Most of the popular CD creation programs allow you to "link" one or more earlier sessions to the session currently being burned. This allows the files from the previous sessions to appear in the last session without taking up any additional space on the CD (except for the directory entry). You can also "remove" or "replace" files, by putting a newer version into the last session, and not including a link to the older version. In contrast, when you put an audio CD into a typical CD player, it only looks at the first session. For this reason, multisession writes don't work for audio CDs, but as it happens this limitation can be turned into an advantage. See section (3-14) for details. This limitation does *not* mean you have to write an entire audio CD all at once; see section (2-9) for an overview of track-at-once writing. Disc-at-once (DAO) writes the entire CD in one pass, possibly writing multiple tracks. The entire burn must complete without interruption, no further information may be added. Track-at-once (TAO) allows the writes to be done in multiple passes. There is a minimum track length of 300 blocks (600K for typical data CDs), and a maximum of 99 tracks per disc, as well as a slight additional overhead associated with stopping and restarting the laser. Because the laser is turned off and on for every track, recorder leaves a couple of blocks between tracks, called run-out and run-in blocks. done correctly, blocks will be unnoticeable. CDs with tracks that run together will have a barely noticeable "hiccup". leaving you 2-second gaps even if original didn't have them. A few recorders, such as the Philips CDD2000, allow "session-at-once" (SAO) recording. This gives you disc-at-once control over the gaps between tracks, and allows you to write in more than one session. This can be handy when writing CD Extra discs (see section CDserror correction? CDs use all 2352 bytes per block for sound samples, while CD-ROMs use only 2048 bytes per block, with most of the rest going to ECC (Error Correcting Code) data. CD uses CIRC (Cross-Interleaved Reed-Solomon Code) encoding. Every CD has two layers of error correction, C1 corrects bit errors at the lowest level, C2 applies to bytes in a frame (24 bytes per frame, 98 frames per block). In addition, data is interleaved and spread over large arc. (This is why you should always clean CDs from center out, not in a circular motion.) If too many errors, CD player will interpolate samples to get a reasonable value. This way you don't get nasty clicks and pops in your music, even if the CD is dirty and the errors are uncorrectable. Interpolating adjacent data bytes on CD-ROM wouldn't work very well, hence need for additional ECC and EDC (Error Detection Codes). disc that you can add data to "open". changing from "open" to "closed" called "finalizing", "fixating", or just plain "closing" the session. When you close last session, you have finalized, fixated, or closed the disc. single-session disc has lead-in, which has Table of Contents (or TOC); program area, with the data and/or audio tracks; lead-out,which doesn't have anything meaningful in it. "open"single-session doesn't lead-in or lead-out written. you write data to a disc and leave session open, TOC --is written into a separate area PMA called the Program Memory Area, or PMA. CD recorders are only devices know to look at PMA, which is why you can't see data in an open session on a standard playback device. CD players won't find any audio tracks, and CD-ROM drives won't see a data track. When the session is finalized, the TOC is written in the lead-in area, enabling other devices to recognize the disc. (Something to try: write an audio track to a blank CDand leave the session open. Put disc in a CD player. Some players will deny the existence of disc, some will spin disc up to an incredible speed and won't even brake spindle when you eject disc, others will perform equally random acts. TOC is important!) If you close the current session and open a new one, the lead-in and lead-out of the current session will be written. A TOC will be written in the current lead-in that points to the eventual TOC of the next session. This process is repeated for every closed session, resulting in a chain of links from one lead-in area to the next. The CD player in your car or stereo system doesn't know about chasing TOC links, so it can only see tracks in the first session. Your CD-ROM drive, unless it's broken or fairly prehistoric, will know about multisession discs and will happily return the first session, last session, or one somewhere in between, depending on what the OS tells it and what it is capable of. DAO If you use disc-at-once (DAO) recording, lead-in is written at very start of process, contents of the TOC are known ahead of time. Drives that allow you to leave the disc open are said to do "session-at-once" recording, or SAO. If Win95 or WinNT, Auto Insert Notification feature will "discover" CD-R as soon as TOC is written. can cause write process to fail. Many of current CD recording software packages will automatically disable AIN for this reason. In track-at-once mode, it will fail during finalization; in disc-at-once mode, it will fail near the beginning of the write process. In both cases, test writes will succeed, because the TOC doesn't get written during a test pass. Packet-written discs follow same rules with regard to open and closed sessions, which is why they have to be finalized before they can be read on a CD-ROM drive. "Packet Writing - Intermediate" document the primer at http://www.mrichter.com/cdr/primer/primer.htm goes into a little more detail on this subject. (Some people like to refer to packet writing as "PAO", for packet-at-once.) SCMS is Serial Copy Management System. goal is to allow consumers to make copy of an original, but not a copy of a copy. SCMS will affect you if you use consumer-grade audio equipment.Professional-grade equipment and recorders that connect to your computer aren't restricted. system works by encoding whether or not material is protected, and whether or not disc is an original. encoding is done with a single bit either on, off, or alternating on/off every five frames. value is handled as follows: Unprotected material: copy allowed.data written is also marked unprotected. Protected material, original disc: copy allowed. data written will be identified as a duplicate. Protected material, duplicate: copy not allowed. There are hardware "SCMS strippers", primarily used in conjunction with a DAT deck, that strip SCMS bits out of an S/PDIF connection. Some of these reportedly introduce unacceptable artifacts into audio. It's possible to "wash" audio by converting it to and from analog format, but again the quality will suffer. TOC (Table Of Contents) identifies start position and length of tracks on a disc. ISO" is a file that contains the complete image of a disc. Such files often used transferring CD-ROM images over Internet. "ISO" is created by copying an entire disc, f rom sector 0 to the end, into a file. Because the image file contains "cooked" 2048-byte sectors and nothing else, it isn't possible to store anything but a single data track in this fashion. .DAT" file could be most anything, usually it's a video file pulled off of a VideoCD. program at http://www.vcdgear.com/ can convert .DAT to .MPG, and recording programs like Nero can record them directly. A ".ISO" file that contains an image of an ISO-9660 filesystem can be manipulated in a number of ways: it can be written to a CD-ROM; mounted as a device with the Linux "loopback" filesystem (e.g. "mount ./cdimg.iso /mnt/test -t iso9660 -o loop"); copied to a hard drive partition and mounted under UNIX; or viewed with WinImage (section (6-2-2)). There is no guarantee, however, that a ".ISO" file contains ISO-9660 filesystem data. And it is quite common to hear people refer to things as "ISO" which aren't. "ISOBuster", from http://www.ping.be/vcd/isobuster.html, can work with some non-ISO-9660 formats, including .BIN. CD-RW CD-Rewritable. CD-R discs are write-once. used just like CD-R discs. CD-RW drives use phase-change technology. Instead of creating "bubbles" and deformations in recording dye layer, state of material in the recording layer changes from crystalline to amorphous form. different refractive indicies, and so can be optically distinguished. These discs are not writable by standard CD-R drives, nor readable by most older CD readers (the reflectivity of CD-RW is far below CD and CD-R, so an Automatic Gain Control circuit is needed to Most new CD-ROM drives do support CD-RW media, but not all them will read CD-RW discs at full speed. CD-R was designed to be read by an infrared 780nm laser. DVD uses a visible red 635nm or 650nm laser, which aren't reflected sufficiently by the organic dye polymers used in CD-R media. Some DVD players come with two lasers so that they can read CD-R. Data Storage: DVD vs. CD DVDs can store more data than CDs for a few reasons: Higher density data storage Less overhead, more area Multi-layer storage Higher Density Data Storage Single-sided, single-layer DVDs can store about seven times more data than CDs. A large part of this increase comes from the pits and tracks being smalleron DVDs. Specification CD DVD Track Pitch 1600nm 740nm Minimum Pit Length (single-layer DVD) 830nm 400nm Minimum Pit Length (double-layer DVD) 830nm 440nm On a CD, a lot of extra information encoded on disc to allow for error correction -- this information is really just a repetition of information that is already on the disc. error correction scheme that a CD uses is quite old and inefficient compared to method used on DVDs. DVD format doesn't waste as much space on error correction, enabling it to store much more real information. Another way that DVDs achieve higher capacity is by encoding data onto a slightly larger area of disc than is done on a CD. Multi-Layer Storage To increase storage capacity even more, DVD can have up to four layers, two on each side.laser that reads the disc can actually focus on second layer through first layer. Here is a list of the capacities of different forms of DVDs: Format Capacity Approximate. Movie Length Single Sided/Single Layer 4.38 GB 2 hours Single Sided/Double Layer 7.95 GB 4 hours Double Sided/Single Layer 8.75 GB 4.5 hours Double Sided/Double Layer 15.9 GB Over 8 hours You may be wondering why the capacity of a DVD doesn't double when you add a whole second layer to the disc. is because when a disc is made with two layers, pits have to be a little longer, on both layers, than when a single layer is used. This helps to avoid interference between the layers, which would cause errors when the disc is played. movies put onto DVDs, encoded in MPEG-2 format The MPEG-2 Format and Data Size Reduction movie is filmed at a rate o 24 frames per second. NTSC,displays 30 frames per second; in a sequence of 60 fields, PAL format, displays at 50 fields per second, but at a higher resolution MPEG encoder that creates the compressed movie file analyzes each frame and decides how to encode it. eliminate redundant or irrelevant data. also uses information from other frames Each frame can be encoded in one of three ways: intraframe, contains complete image data for frame. predicted frame contains just enough information to tell DVD player how to display frame based on most recently displayed intraframe or predicted frame. data of how picture has changed from previous frame. bidirectional frame. uses interpolation, to calculate the position and color of each pixel. newscast lot more predicted frames scene is unaltered from one frame to the next. fast action scene more intraframes would have to be encoded. MPEG Moving Picture Experts Group (MPEG) a working group of ISO/IEC in charge of the development of standards for coded representation of digital audio and video. Established in 1988, the group has produced MPEG-1, standard on which such products as Video CD and MP3 are based, MPEG-2 the standard on which such products as Digital Television set top boxes and DVD are based and MPEG-4, the standard for multimedia for the web and mobility. current thrust is MPEG-7 "Multimedia Content Description Interface whose completion is scheduled for July 2001. Work on the new standard MPEG-21 "Multimedia Framework" has started in June 2000 and has already produced a Draft Technical Report. S DVD Audio difference in sound quality should be noticeable. will need a DVD player with a 192kHz/24-bit digital to analog converter. Most DVD players have only a 96kHz/24-bit digital to analog converter. CDs can hold 74 minutes of music. DVD audio discs can hold 74 minutes of music at 192kHz/24-bit audio. DVD audio disc can hold almost 7 hours of CD quality audio. CD Audio DVD Audio Sampling Rate 44.1 kHz 192 kHzSamples Per Second 44,100 192,000 Sampling Accuracy 16-bit 24-bit of Possible Output Levels 65,536 16,777,216 CD Reading pits polycarbonate itself is part of optical system for reading pits. index of refraction is 1.55. Laser light incident on polycarbonate surface will be refracted at a greater angle into surface. Thus, original incident spot of around 800 microns (entering polycarbonate) will be focused down to about 1.7 microns (at metal surface). This is a major win, as it minimizes effects of dust and scratches on surface. The laser used for CD player is typically an AlGaAs laser diode with a wavelength in air of 780 nm. (Near infrared -- your vision cuts out at about 720 nm). The wavelength inside polycarbonate is a factor of n=1.55 smaller -- or about 500 nm. [Lost in maze of pages-Reload Imagemap] Laser Pickup System The digital data on a CD is represented by bumps, where edge of each bump represents a one. The bumps are read by a laser that is part of laser pickup system. (See section on Optical Train) The laser pickup system includes thelaser diode, mirrors and lenses, and photodetectors. The laser beam (which is produced by laser diode) is directed on to CD via mirrors and lenses. When beam strikes CD, beam is reflected and directed to photodetectors. Photodetectors are transducers that convert light into an electric signal. So information reflected off of CD is converted to an electrical signal and sent to servo and data decoding systems via photodetectors. [Lost in maze of pages-Reload Imagemap] History In 1983 compact disc (CD) players entered consumer market. By 1986, CD players were selling at rate of over one million per year, making CD player fastest growing consumer electronic product ever introduced. So whose idea was it to reproduce music digitally on a CD? The design and development of CD player was a collaboration of two companies: Philips and Sony. Philips was first to come up with idea of optical-disc audio reproduction. They had developed a laser-scanned videodisk player called LaserVision -- which lead them to idea of developing a similar kind of system to reproduce sound. Philips decided to produce a prototype and present it to manufacturers. In process of building their prototype, they found that error detection and correction was imperative but they did not know an efficient way of implementing it. They decided to present their prototype, anyway, to several manufactures in Japan. Of five manufacturers present at demonstration, Sony was only manufacturer who decided to work with Philips on compact disc player. Sony was leader in magnetic-tape recording and digital conversion techniques. Because of complimentary knowledge between two companies, they where able to solve error correction and detection problem along with developing an industry standard for format of compact discs. In 1981, thirty-five electronics manufacturers agreed on Philips/Sony standard, and race was on to produce first compact disc player. Do you know who won? With Philips struggling on implementation of digital electronics, Sony's expertise in that area allowed them to produce first CD player one month earlier than Philips. fundamental ideas underlying compact disk player The basic ideas behind a compact disc player are quite fundamental, but true marvel is in engineering and manufacturing of this consumer electronic product. Music stored on a CD is in digital form. When music is stored digitally, it requires a tremendous amount of storage space. For example, one second of sound takes up over a million bits of digital information. If you were to try and store this information on a floppy disk it would hold less than three seconds of music! A very dense digital storage medium is needed to store digital music. The problem of dense storage media was solved by using a laser to read off data bits on an optical disc. Data can be crammed much tighter on a CD than on a magnetic floppy or hard drive because a laser beam can be focused to a much smaller point than magnetic heads. One second of music can now be stored on a CD in an area size of a pin head! Actually, a total of 15 billion bits of information can be stored on a music CD which equates to about 74 minutes of continuous stereo music. It would take over 1,480 floppy disks to store that much information and you certainly wouldn't get continuous stereo music! [Lost in maze of pages-Reload Imagemap] 3-beam auto focusing If objective lens is closer to compact disk than focal length of object lens, then cylindrical lens creates an elliptical image on photodetector array. If objective lens is further away from compact disk than focal length of object lens, then cylindrical lens again creates an elliptical image on photodetector array. However, this elliptical image is perpendicular to first image. Of course, if disk is right at focal length of objective lens, then cylindrical lens does not affect image and it is perfectly circular. So, if disk is too far away -- then quadrants D and B will get more light than quadrants A and C. Similarly, if disk is too close -- then quadrants A and C will get more light than D and B. A simple circuit generates an autofocus signal based upon output of photodetector. The output of this correction signal can be used to drive a simple auto-focus servo. A typical example of such a servo is illustrated below. [Lost in maze of pages-Reload Imagemap] Data Decoding System When photodetectors translate reflected light to an electrical signal, signal represents a string of ones and zeros that is encoded and modulated. The job of decoding system is to demodulate and decode data string and convert it to music. The data decoding system entails several subsystems: demodulator, error detection and correction (EDC), demultiplexor, and digital-to-analog converters. The demodulator circuit performs opposite function as EFM circuit. It demodulates data string before EDC circuitry begins decoding. After data is demodulated, subcode is available to control system. Subcode contains information such as track number, time left on track, and time left on CD. The EDC circuits decode CIRC code that is embedded in digital music. The decoding process detects and corrects errors that are found on CD. Types of errors found on CD's are random types and burst types. Random errors entail a couple of damaged bumps at a time and usually occur during manufacturing process of CD. Burst errors are many consecutive damaged bumps that can span up to a couple thousand bumps. An example of these are scratches, animal hair, or finger prints. The error detection and correction circuits can correct, conceal , or in extreme circumstances mute errors on CD. After EDC circuits, data is almost in its original music form. At this point, both right and left channels are in same continuous stream of data. This stream is sent to a demultiplexor where two channels are separated and each one is sent to a digital-to-analog converter (DAC). Some system have only one DAC so demultiplexor is after DAC. The DAC is a circuit that converts a digital signal to an analog signal. This is final circuit in CD player, and it outputs electrical signal to your stereo, headphone, or speakers. [Lost in maze of pages-Reload Imagemap] Simple Error Detection and Correction Codes Error detection and correction codes are fundamental to operation of any digital storage system. There are literally thousands of such codes. These codes typically rely on using additional bits (usually called parity bits) to carry error detection and correction information. In a simple binary parity check, a parity bit is a single bit that represents whether total number of "1s" in a particular data stream is even (1) or odd (0). (Modulo two addition). For example, assume that you are setting a parity bit over all digits of following word. 1101 0000 The total number of "1s" is odd, so parity bit would be 1. The word might then be written as 1101 0000 1 where last digit is parity bit. Even simple binary parity checks can become quite complex if more than one parity bit is used. For example, you may elect to have two parity bits -- one on first four bits of word and one on last four. 1 1 0 1 0 0 0 0 P1 P2 x x x x 1 x x x x 0 If enough parity bits are used, then error can not only be detected -- they can also be corrected. For example, consider what happens if you use four parity bits. The first one is on first four bits, second one is on second four bits, third one is on 1,2,5,6 bits and fourth one is on 2,3,6,7 bits. 1 1 0 1 0 0 0 0 P1 P2 P3 P4 x x x x 1 x x x x 0 x x x x 0 x x x x 1 Now, assume that there was an error in final bit. 1 2 3 4 5 6 7 8 P1 P2 P3 P4 1 1 0 1 0 0 0 1 1 0 0 1 x x x x 1 x x x x 1 x x x x 0 x x x x 1 Parity bit P1 would agree with parity bit in transmitted word, P2 would NOT agree, P3 and P4 would agree. Since P2 is only parity bit not agreeing with transmitted word -- then error must be in 8th bit. Unfortunately, majority of error-detection and correction algorithms used in CD players are not as simple as binary check codes discussed above. Although an overview of these codes will be presented, in-depth analysis of codes is beyond scope of this course. (Interested students should consult more advanced references, such a W. Peterson, Error-Correcting Codes, MIT Press) Interpolation: In this technique, some average is constructed using valid data around an error. This average is then substituted in for erroneous data. Since most music (with possible exception of heavy metal!) is continuous -- this method works well for concealing relatively short errors. Muting: Muting is a last ditch technique -- as it effectively creates a brief period of silence in audio train. However, it is not effective to simply set all binary digits to zero --as this produces exactly click that we are trying to avoid! Instead, volume is faded out and then back in again to conceal error. [Lost in maze of pages-Reload Imagemap] EFM modulation EFM means Eight to Fourteen Modulation and is an incredibly clever way of reducing errors. The idea is to minimize number of 0 to 1 and 1-0 transitions -- thus avoiding small pits. In EFM only those combinations of bits are used in which more than two but less than 10 zeros appear continuously. For example, a digital 10 given as a binary 0000 1010 is an EFM 1001 0001 0000 00 (See attached table for complete list of EFM codes[1].) Click here for Table 1 Click here for Table 2 The use of EFM coding means that pits come in discrete lengths ranging from 3 bits long (often written 3T) to 11 bits long (11T). As laser beam scans across these pits, a very distinct RF signal is formed. The shortest wavelength in this signal (highest frequency) is produced by 3T pits. The longest wavelength in signal (lowest frequency) is produced by 11T pits. The zero crossings of RF signal represent edges of pits -- and thus binary "1s" in data stream[2]. (Notice that longer wavelength, larger amplitude of signal.) It is common to display photodetector output on a scope with a conventional trigger. This results in a display where nine possible frequencies (3T to 11T) all add up on top of each other. This type of display is termed an "eye" pattern and provides valuable information about various alignment parameters of CD player. Notice that relationship between size and wavelength is very distinct in eye pattern[3]. The RF output is converted to a square wave, and then phase locks a clock with period T. The CD player then begins to hunt for characteristic start of frame symbol, which is three transitions separated by 11T. (100000000001000000000010 + 3 merge bits) Then, player isolates 33 17T symbols, and then kicks off 3T merge bits -- leaving 33 14T active symbols. [Lost in maze of pages-Reload Imagemap] Subcodes The 8-bit subcode is a very peculiar creature. Each 588 bit frame has an eight bit subcode. These bits are named P-Q-R-S-T-U-V-W. So, for each 588 bit frame, there is one P bit (not same as P parity), one Q bit (not same as Q parity), one R bit, one S bit and so on[5]. Now, P-Q-R-S-T-U-V-W bits from 98 consecutive frames are collected together. These 98 bits are called a subcoding channel or just channel. Thus, there is a P-channel of 98 bits (no relation to P parity), a Q-channel of 98 bits (no relation to Q parity), an R-channel of 98 bits and so on. Unfortunately (just to maximize confusion with P and Q parity bits) only P and Q subcode channels are used. The R-W subcode channels are not yet assigned -- being held for later expansion of standard. [Lost in maze of pages-Reload Imagemap] P Channel The P channel simply designates starting and stopping of tracks. Music data is denoted by all zeros, start flag before musical selection by 2-3 seconds of "1's". The lead out at end of disk is a 2 Hz alternating 1 and 0[6]. [Lost in maze of pages-Reload Imagemap] Q channel The Q channel contains majority of program and timing information. The first two bits (S0 and S1) are synchronization bits. The next four (bits 3-6) are control bits. Bit 3 controls number of channels (2 or 4), bit 4 is unassigned, bit 5 is copy protect and bit 6 is pre-emphasis bit. The next four bits control mode (three defined modes). The next 72 bits are data -- and last 16 are a cyclic redundancy check on channel data. Mode 1 contains primary selection timing information. In lead-in area, this information consists of number of tracks and absolute starting time of each track. This information is continually repeated in lead-in area, and allows CD player to build table of contents[7]. In program and lead-out areas, Mode 1 information is track number, index numbers within a track, time within a track, and absolute time[8]. Mode 2 contains a catalog number of disk -- plus a continuation of absolute time count[9]. Mode 3 contains IRSC codes for identifying each track -- allowing for such things as automatic copyright logging. Mode 3 also contains a continuation o f absolute time count. Mode 3 is irregularly used at this time[10]. [Lost in maze of pages-Reload Imagemap] Q channel The Q channel contains majority of program and timing information. The first two bits (S0 and S1) are synchronization bits. The next four (bits 3-6) are control bits. Bit 3 controls number of channels (2 or 4), bit 4 is unassigned, bit 5 is copy protect and bit 6 is pre-emphasis bit. The next four bits control mode (three defined modes). The next 72 bits are data -- and last 16 are a cyclic redundancy check on channel data. Mode 1 -- contains primary selection timing information. In lead-in area, this information consists of number of tracks and absolute starting time of each track. This information is continually repeated in lead-in area, and allows CD player to build table of contents[7]. In program and lead-out areas, Mode 1 information is track number, index numbers within a track, time within a track, and absolute time[8]. Mode 2 contains a catalog number of disk -- plus a continuation of absolute time count[9]. Mode 3 contains IRSC codes for identifying each track -- allowing for such things as automatic copyright logging. Mode 3 also contains a continuation o f absolute time count. Mode 3 is irregularly used at this time[10]. [Lost in maze of pages-Reload Imagemap] IEC-908 The BIG picture The encoding of digital audio on CD player is governed by IEC 908. This standard is available in library for your perusal. (Notice that every other page is missing -- this is because standard is written in both French and English and I took out French pages!) This information is also covered more generally in Chapter 3 of Ken Pohlman's book The Compact Disk Handbook, (A-R Editions, 1992). CD players use parity and interleaving techniques to minimize effects of an error on disk. In theory, combination of parity and interleaving in a CD player can detect and correct a burst error of up to 4000 bad bits -- or a physical defect 2.47 mm long. Interpolation can conceal errors up to 13,700 or physical defects up to 8.5 mm long. The entire error detection and correction algorithm is summarized on following table. This is Figure 12 from IEC 908 standard. This table will be described in more detail below. The original musical signal is a waveform in time. A sample of this waveform in time is taken and "digitized" into two 16-bit words, one for left channel and one for right channel. For example, a single sample of musical signal might look like: L1 = 0111 0000 1010 1000 R1 = 1100 0111 1010 1000 Six samples (six of left and six of right for a total of twelve) are taken to form a frame. L1 R1 L2 R2 L3 R3 L4 R4 L5 R5 L6 R6 The frame is then encoded in form of 8-bit words. Each 16-bit audio signal turns into two 8-bit words. L1 LI R1 R1 L2 L2 R2 R2 L3 L3 R3 R3 L4 L4 R4 R4 L5 L5 R5 R5 L6 L6 R6 R6 This gives a grand total of 24 8-bit words. This is column two on IEC 908 table. The even words are then delayed by two blocks and resulting "word" scrambled. This delay and scramble is first part of interleaving process. The resulting 24 byte word (remember, it has an included two block delay -- so some symbols in this word are from blocks two blocks behind) has 4 bytes of parity added. This particular parity is called "Q" parity. Parity errors found in this part of algorithm are called C1 errors. More on Q parity later. Now, resulting 24 + 4Q = 28 bytes word is interleaved. Each of 28 bytes is delayed by a different period. Each period is an integral multiple of 4 blocks. So first byte might be delayed by 4 blocks, second by 8 blocks, third by 12 blocks and so on. The interleaving spreads word over a total of 28 x 4 = 112 blocks. The resulting 28 byte words are again subjected to a parity operation. This generates four more parity bytes called P bytes which are placed at end of 28 bit data word. The word is now a total of 28 + 4 = 32 bytes long. Parity errors found in this part of algorithm are called C2 errors. More on P parity later too. Finally, another odd-even delay is performed -- but this time by just a single block. Both P and Q parity bits are inverted (turning "1s" into "0s") to assist data readout during muting. An 8-bit subcode is then added to front end of word. The subcode specifies such things as total number of selections on disk, their length, and so on. More on this later. Next data words are converted to EFM format. EFM means Eight to Fourteen Modulation and is an incredibly clever way of reducing errors. The idea is to minimize number of 0 to 1 and 1-0 transitions -- thus avoiding small pits. In EFM only those combinations of bits are used in which more than two but less than 10 zeros appear continuously. For example, a digital 10 given as a binary 0000 1010 is an EFM 1001 0001 0000 00 Each frame finally has a 24-bit synchronization word attached to very front end -- (just for completeness word is (100000000001000000000010) and each group of 14 symbols is then coupled by three merge bits. These merge bits are chosen to meet two goals: 1. No adjacent 1's from neighboring EFM encoded words Remember that there are lots of EFM words which end in "1" -- as one example, all eight-bit binary words from 128 to 152 end in "1". Similarly, there are EFM words that start in "1". Thus, it is relatively straightforward to have to have adjacent EFM words that create adjacent "1s". For example -- binary 128 and binary 57 10000000 in EFM is 00111001 in EFM is 01001000100001 10000000001000 2. The digital sum value is kept near zero Minimizing digital sum value is just an attempt to keep average number of "0's" and "1's" about same. The value of +1 is assigned to "1" states and value of -1 is assigned to "0" states. Then, value of merge bit is chosen to maintain average near zero. SO! The final frame (which started at 6*16*2 = 192 data bits) now contains: 1 sync word 24 bits 1 subcode signal 14 bits 6*2*2*14 data bits 336 bits 8*14 parity bits 112 bits 34*3 merge bits 102 bits GRAND TOTAL 588 bits [Lost in maze of pages-Reload Imagemap] Simple interleaving Interleaving is a very simple and powerful idea. To illustrate interleaving, assume that you have a frame consisting of several characters of information, U N I V E R S I T Y O F W A S H I N G T O N Assume that you spit on disk and destroy several of characters. R S I T Y O F W A S H I N G T O N The first word is then very hard to reconstruct! However, you can take original frame and scramble it as, U N I V E R S I T Y O F W A S H I N G T O N O N S T H U G R F S I I O T W N N V E I Y A Then you can damage it, U G R F S I I O T W N N V E I Y A Then you can unscramble it, U N I V E R I Y O F W A S I G T N It is much easier to "interpolate" or "guess" missing letters. (A bit like later stages of "hangman"!) [Lost in maze of pages-Reload Imagemap] P and Q parity The eight parity symbols are calculated from following equations: Hp . Vp = 0 Hq . Vq = 0 Definitions for H and V are as follows. V is pretty straightforward, just being shifted and interleaved data bits in data word (including parity bits). However, H is more complex. H is defined on Galois field GF (28) by polynomial: (The 's in definitions for H vector come from field elements of Galois field.) Unfortunately, Galois field of 28 elements of GF (28) defined by is a set of 255 's. However, to illustrate principle, Galois field of 24 elements of GF (24) formed as field of polynomials over GF(2) modulo is given on next page[4]. 0 = 1 = 0001 1 = 1 = 0010 2 = 2 = 0100 3 = 3 = 1000 4 = 1 + 1 = 0011 5 = 2 + 1 = 0110 6 = 3 + 2 = 1100 7 = 3 + 1 + 1 = 1011 8 = 2 + 1 = 0101 9 = 3 + 1 = 1010 10 = 2 + 1 + 1 = 0111 11 = 3 + 2 + 1 = 1110 12 = 3 + 2 + 1 + 1 = 1111 13 = 3 + 2 + 1 = 1101 14 = 3 + 1 = 1001 15 = 1 = 0 [Lost in maze of pages-Reload Imagemap] Pit Edges A CD disk contains a long string of pits written helically on disk. The edges of pits correspond to binary "1"s. [Lost in maze of pages-Reload Imagemap] The CD disk The CD disk is a 120 mm diameter disk of polycarbonate. The center contains a hole 15 mm in diameter. The innermost part of disk does not hold data. The active data area starts at 46 mm diameter location and ends at 117 mm diameter location. The 46-50 mm range is lead in area and 116-117 range is lead out area. Disks are written from center to outside (this increases manufacturing yield, and also allows for changes in disk size). [Lost in maze of pages-Reload Imagemap] Fabrication The fabrication of a CD disk is a fascinating process. This process is discussed in some detail in The Compact Disk Handbook, Chapter 7 and only high points are summarized here. The process begins by making "glass master". To do this, a glass plate about 300 mm in diameter is lapped flat and polished. The plate is coated with photoresist. A mastering tape is made containing information to be written on disk. A laser then writes pattern from master tape into photoresist. The photoresist is developed. A layer of metal (typically silver over a nickel flash) is evaporated over photoresist. The master is then checked for accuracy by playing disk. The master is then subject to an electroforming process. In this electrochemical process, additional metal is deposited on silver layer. When metal is thick enough (typically a few mm's) metal layer is separated from glass master. This results in a metal negative impression of disk -- called a father. The electroplating process is then repeated on father. This typically generates 3-6 positive metal impressions from father before quality of father degrades unacceptably. These impressions are called "mothers". The electroplating process is repeated again on mothers. Each mother typically makes 3-6 negative metal impressions called sons or stampers. The sons are suitable as molds for injection molding. Polycarbonate is used to injection mold CD disks. Once disks are molded, a metal layer is used to coat disks. Aluminum, gold, copper and silver are all reflective enough to be optically acceptable. Gold is typically too expensive and copper has a peculiar appearance. Thus, aluminum and silver are most commonly used metals. Following metal deposition, a thin plastic layer (1-30 microns) is spin-coated on over metal. This can be a nitrocellulose layer suitable for air drying, or an acrylic plastic that is cured in UV. Finally, logo and other information is silk screened on top. [Lost in maze of pages-Reload Imagemap] Servo System The servo system is responsible for thefocusing and tracking of laser beam on CD. This is not an easy task since distance between pits is extremely small (1.6 micrometers) and beam must be focused to a tiny point of 0.7 millimeters. Also, CD is not completely flat -- so when it is spinning CD wobbles. So how does laser pickup system stay on track and in focus? As mentioned before, signal from photodetectors goes to both data decoder system and servo system. The photodetectors provide feedback to laser pickup system via servo system. The servo system uses servomechanisms (servos) to make minute changes in tracking or focusing. The servos are typically moving-coil actuators. These actuators can be found in laser pickup system. The actuators move objective lens either toward or away from CD for focusing, and sideways for tracking. As you listen to music from CD player, servo system is continuously making minute adjustments to tracking and focusing so that you can hear error free music. [Lost in maze of pages-Reload Imagemap] 3-beam tracking When laser beam goes through diffraction grating, it is split up into a central bright beam plus a number of side beams. The central beam and one beam on each side are used by CD for tracking system. Consider a segment of CD player containing several tracks. If optical head is on track, then primary beam will be centered on a track (with pits and bumps) and two secondary beams will be centered on land. The three spots are deliberately offset approximately 20 microns with respect to each other. Two additional detectors are placed alongside main quadrant detector in order to pick up these subsidiary beams. If three beams are on track, then two subsidiary photodetectors have equal amounts of light and will be quite bright because they are only tracking on land. The central beam will be reduced in brightness because it is tracking on both land and pits. However, if optical head is off track, then center spot gets more light (because there are fewer pits off track) and side detectors will be misbalanced. [Lost in maze of pages-Reload Imagemap] Pits and land Each pit is approximately 0.5 microns wide and 0.83 microns to 3.56 microns long. (Remember that wavelength of green light is approximately 0.5 micron) Each track is separated from next track by 1.6 microns. The area between pits is termed "land". So, a highly magnified section of track might look something like: [Lost in maze of pages-Reload Imagemap] Pits and common object sizes Pits are formed in polycarbonate disk by an injection molding process. As such, they represent some of smallest mechanically fabricated objects made by humans. The width of a CD pit is approximately wavelength of green light. The tracks are separated by approximately three times wavelength of green light. Diffraction from these features (so very close to wavelength of light) is what gives CD disks their beautiful colors. A thin layer (50-100 nm) of metal (aluminum, gold or silver) covers pits. An additional thin layer (10-30 microns) of polymer covers metal. Finally, a label is silk-screened on top. Notice that pits are far closer to silk screened side of disk (20 microns) than they are to read-side of disk (1.55 mm). Thus, it is easier to permanently damage a disk by scratching top -- than bottom! For more on fabrication, click here [Lost in maze of pages-Reload Imagemap] 3-beam pickup The most common optical train in modern CD players is three beam pick-up, depicted below. The light is emitted by laser diode and enters a diffraction grating. The grating converts light into a central peak plus side peaks. The main central peak and two side peaks are important in tracking mechanism. The three beams go through a polarizing beam splitter. This only transmits polarizations parallel to page. The emerging light (now polarized parallel to page) is then collimated. The collimated light goes through a 1/4 wave plate. This converts it into circularly polarized light. The circularly polarized light is then focused down onto disk. If light strikes "land" it is reflected back into objective lens. (If light strikes pit, now a bump, it is not reflected.) The light then passes through 1/4 wave plate again. Since it is going reverse direction, it will be polarized perpendicular to original beam (in other words, light polarization is now vertical with respect to paper). When vertically polarized light hits polarizing beam splitter this time, it will be reflected (not transmitted as before). Thus, it will reflect though focusing lens and then cylindrical lens and be imaged on photodetector array. The cylindrical lens is important in auto-focusing mechanism. [Lost in maze of pages-Reload Imagemap] Control and Display System The control system processes subcode that is encoded on CD. The subcode tells information like: how many tracks are on CD, what track it is presently on, time left on song, or time left on CD. With this information, control can send speed up or slow down commands to disc drive motor. Because of subcode information, CD player has many features that simply cannot be accomplished on record players or tape decks. Some examples of various features are following: random memory programming, manual searches (skipping forward or backward with touch of a button), random playback, and pausing. The control system can display quite a bit of information also: what present track is, time left on track, time left on CD, and time left in memory program (if you did memory programming). Finally, control system provides an interface with control buttons and knobs on CD player. When a user presses 'skip' button, control system senses command and sends control signals to various subsystems to perform 'skip' command. It also displays requested task at hand. If you want to learn more about CD player look in Further Reading section. All of these books can be found at public libraries. You can also call publisher to purchase your own book. You might call University of Washington bookstore first. Chances are they may have it, or be able to order it for you. [Lost in maze of pages-Reload Imagemap] Quarter-wavelength Pits The CD disk is actually read from bottom. Thus, from viewpoint of laser beam reading disk, "pit" in CD is actually a "bump". The pit/bump is carefully fabricated so that it is a quarter of a wavelength (notice a wavelength INSIDE polycarbonate) high. The idea here is that light striking land travels 1/4 + 1/4 = 1/2 of a wavelength further than light striking top of pit. The light reflected from land is then delayed by 1/2 a wavelength -- and so is exactly out of phase with light reflected from pit. These two waves will interfere destructively -- so effectively no light has been reflected. [Lost in maze of pages-Reload Imagemap] =====================SIGNAL_FREQUENCY======================================= Long wave below 550Khz 510 -535 Misc Radio beacons 500 KHz Distress(CW) ship to shore 415-490KHz Maritime mobile (CW) ship to shore 285-400KHz Radio beacons,weather weath,AM, carrierCurrent_60Hz_trans aeronautical and marine 190-285KHz Radio beacons,weather weath,AM, carrierCurrent_60Hz_trans european long wave broadca 160-190KHz Fixed Public,license-free exper 1W , no need licen experiimental european long wave broadcast fixed(point to point) 110-160KHz maritime mobile, noisy, some RTTY trans lowest freq long wave broadcast fixed(point to point) 90-110KHz Loran Navigation 30-90KHz fixed,mobile RTTY trans, some CW , noisy standard freq /time sign 14-30KHz submarine comunications RTTY trans, some CW , noisy VLF wold wide hig-power miltary and commercial 10-14KHz atm phenomena, whistlers lowest radio sprect freq used omega signals freq standard below 10KHz atmoshper noise whistlers experimental experiment trans miltary AM radio: 535 kilohertz to 1.7 megahertz Short wave radio: 5.9 megahertz to 26.1 megahertz Citizens Band (CB) 26.96 megahertz to 27.41 megahertz Television stations 54-88 megahertz for channels 2-6 FM radio 88 megahertz to 108 megahertz Television stations 174-220 megahertz for channels 7-13 Garage door openers around 40 megahertz alarm systems around 40 megahertz cordless phones: Bands from 40 to 50 megahertz Baby monitors: 49 megahertz RC airplanes: around 72 megahertz, which is different from... RC cars: around 75 megahertz Wildlife tracking collars: 215 to 220 megahertz MIR space station: 145 megahertz and 437 megahertz Cell phones: 824 to 849 megahertz 900MHzcordlessphones Obviously around 900 megahertz! scanner cannot listen Air Traffic Control radar: 960 to 1,215 megahertz GPS Global Positioning System: 1,227 and 1,575 megahertz Deep space radio communications: 2290 megahertz to 2300 megahertz aviation band 118 MHz to 135.975 MHz pilot-to-pilot 123.45 MHz into your scanner will let you hear some police/municipality frequencies in the 800 MHz range. most scanners 29-512 megahertz MHz) range. car race 460 to 470 MHz ------------------------------------------------------------- 535-1635 KHz AM 44-49 Mhz Analog cordless phone 54-88 Mhz TV chaneel 2-6 (VHF) 88-108 MHz FM 174-216 Mhz TV channel 7-13MHz (VHF) 470-806 MHz TV Channel 14-69 (UHF) 800 MHz RF wireless modems 806-890 MHz Cellular Phones 900 MHz digital cordless phones 900-929 Mhz Personal Communication services (PCS) 929-932 Mhz Nation wide pagers 932-940 MHz two-way pagers 1610-1626.25 MHz Satellite phones uplink 1850-2200 MHz Future PCS 2483.5-2500 MHz Satellite phones downink 4-6 Ghz Satellite TV large dish 11.7-12.7 Ghz Satellite TV small dish 28-29 GHz Wireless "cable" TV ------------------------------------------------------------- Frequency SPECTRUM 0 Hertz Steady direct current 50-60 Hetz AC power ----------------------USA--------------------------------- 16-16.000 kHz Audio frequencies 5000Km 10-30 kHz v.l.f -very low frequency 30-10Km 30 kHz - 30 MHz Radio Frequencies 30-300 kHz l.f. low frequency 10-1Km 30S35 kHz Marine com & navigation, aero nav. 300-3000 kHz m.f medium frequencies 1000-100m 535-1605 kHz AM broadcast bands 1800-2000 kHz 60 meter band ----------------------Football_Field--------------------------- 3-30 MHz h.f. - high frequencies 100-10m 3.5-4 MHz 80 me1erband 7-7.3 MHz 40 band 14-14.35 Mnl 20 meter band 21-21.45 MHz 15meterbend 26.85-27.54 MHz Industrial, Scientific, medical 28-29.7 MHz 10 meterband 26.86-27.455 MHz Citizens Band Class D ----------------------Human----------------------------------- 30-300 MHz very high frequencies 1O-1m 30-50 MHz Police,fire,highway,railroad 50-54 MHz 6 meter band 54-72 MHz TV channels 2 to 4 72-76 MHz Government, Aero,Marker 75MHz 76-88 MHz TV channels 5 and 6 88-108 MHz FM broadcast band 108-118 MHz Aeronautical navigation 118-136 MHz Civil Communication Band 148-174 MHz Government 144-148 MHz 2 meter band 174-216 MHz TV channels 7 to 13 216-470 MHz Amateur, government. CB Bend non-govemment, fixed or mobile aeronautical navigation 220-225 MHz Amateur band. 1-1/4 meter 225-400 MHz Military 420-450 MHZ Amateur band, 0.7 meter 462.5-465 MHz Citizens Band 300-3000 MHz u.h.f. - ultra high frequencies lOO-1Ocm 470-890 MHz TV channels 14 to 83 890-3000 MHz Aero navigation, amateur bands. Qovernment& non-government, fixed and mobile 1300-1600 MHz Radar band 3000-30,000 MHz s.h.f. - super high frequencies 10-1cm Government and non-govetnment, amateur bands, radio navigation ----------------------Grain_OF_SAND------------------------------- 30 to 300 GHz Extra-high frequencies (weather radar, experimental, government) 1-0.1cm ----------------------Bacterium------------------------------- 30-0.7um Infrared light and heat 0.76-0.39 um Visiblelight 300teraHz 6470-7000 angstroms Red light 5850-6740 angstroms Orange light 5750 5850 angstroms Yellow light 5560-5750 angstroms Maximum visibility 4912-5560 angstroms Green light 4240-4912 angstroms Blue light 4000-4240 angstroms Violet light ----------------------Virus------------------------------- 0.390-0.032um Ultraviolet light 30petaHz 3200-1 angstroms X-rays 1-0.06 angstroms Gamma rays ----------------------Atom------------------------------- 0.0005 angstroms Cosmic rays ----------------------Atomic_Nucleus------------------------------- 1um micrometer(10^-6m) GHz gigahertz(10^9 Hz) angstrom 10^-10 meters ------------------------------------------------------------- MORSE CODE Later Code Letter Code b A .- Q --.- 1 .--- B -... R .-. 2 ..-- C -.-. S ... 3 ...- D -.. T 4 .... E . U ..- 5 ..... F ..-. V ...- 6 -.... G --. W .-- 7 --... H .... X -..- 8 ---.. I .. Y -.-- 9 ----. J .--- Z --.. O ---- K -.- Error ....... . .-.-.- L .-.. wait .-... : --..-- M -- End Msg - -... ; N -. EndWrk ...-.- 0 --- InvXmit-.p ( -.--.- P .--. / -..-. ------------------------------------------------------------- RADIO ALPHABET Letter Word pronunciation A Alfa Al Fah B Bravo Bra Voh C Charlie Char Lee D Delta Del Tah E Echo Ek Oh F Foxtrot Foks Trd G Golf Golf H Hotel Ho Tell I India In Dee Ah J Juliett Jew Lee Ett K Kilo Key Loh L Lima Lee Mah M Mike Mike N November No Vem Bar O Oscar Oss Cahr P Papa Pah Pah Q Ouebec Ke Beck R Romeo Row Me Oh S Sierra See Air Rah T Tango Tang Go U Uniform You Nee Form V Victor Vick Tar W Whiskey Wiss Key X X-Ray Ecks Ray Y Yankee Yang Kee Z Zulu Zoo Loo ======================SIGNAL_RADIO_TV==================================== no channel 1 ? on broadcast TV? ONCE UPON A time, there was one. After World War II, great demand for broadcast locations on the electromagnetic spectrum. Federal Communications Commission re-evaluated in 1945. allocated 44- to 216MHz VHF channels 1 through 13. this move, VHF television took 72- to 76MHz range previously allocated for nongovernmental land and mobile use In 1948, the FCC reallocate beginning of VHF space (44- to 50MHz) to nongovernmental land and mobile use, compensating for the bandwidth lost earlier. was the space that channel 1 occupied. Rather than recalibrate FCC simply deleted channel 1. Maxwell's Equations __ \/ dot J = -delta_p/dt __ \/ cross E = -delta_B/dt V=delta_Phi/dt __ \/ cross H = J+ delta_D/dt H =I*N __ \/ dot D = p __ \/ dot B = 0 exp(j*X) cos(x) +j*sin(x) <---------One line of NTSC-standard color video----> 1.54us 750ns |\ /\ < > < > /|/ \/\/\/|/ \/\/|/|_/\/\|\/\/\ _ __||||_/\/ \__ | | | |||| : | |____| ^ |__COLOR BURST 3.579545MHZ <-------> 4.85us <---> 4.71us <---------------> Horizontal blanking 11.1us <----52.4us video information-....---> 100 IRE 1V................................ White 1.00V |\ /\ /|/ \/\/\/|/ \/\/ 0 IRE 0.3V.._ _|||_/\/ \__black0.25v | | | ||| -40 IRE 0V | |__| sync0.00v <-----------63.5us video information-....----> TV <------H------------> _ _ Horzontial _| |_;;_ _| |_;;_ 15734.25Hz=2/455 chroma | < > | _.... _| <----->| chroma=3,579,545Hz | .075H |_/\/ \/ .13H |_ +/-10Hz _| FIG. 2„A TYPICAL NTSC HORIZONTAL scan line. The blanking interval between lines gives the electron beam time to reset. Over time, a lot of additional information has been placed in the blanking interval. 100 IRE 1V............................................ |\ /\ /|/ \/\/|/ \/\/|/|_/\|\/\ 0 IRE 0.3V.._ __|||_/\/ \__ | | | ||| -40 IRE 0V | |___| <--control-> <--52.4us video information-.--> CONTROL AREA. NTSC video standard signal range 0 to 1 volt pk-to-pk. *** TV <------H---------> _ _ Horzontial _| |_;;_ _| |_;;_ 15734.25Hz =2/455 chroma | < > | .. __| <----->| chroma =3,579,545Hz | .075H |_/\/ \/ .13H |_ +/-10Hz _| Horz = 15734.24 =2/455 times Chroma Vert =59.94Hz =2/52H Horz blank =.18 H Vert blank = 21H ____ LLL|||||LLLLL_|_|_|_| |<-><---><---><----->| |\|\| 3H 8H 8H 12H |_ Vertical =59.594Hz = 2/525 30 frames/sec x y Video 45.76MHz | / R .67 .33 Sound 41.25MHz | / G .21 .71 | / B .14 .08 | / |/____ Color Vector sound press level =SPL=20logP/.0002 P measured in bars 1 bar = 1ATM I=P^2/p*c I=sound intensity p,c=density,speed of sound in air .0002ubars= Iref(0dB)= 1E-16 watts/cm2 <-------One line of NTSC-standard color video---> |\ /\ /|/ \/\/\/|/ \/\/|/|_//\ _ __||||_/\/ \__ | | | |||| : | |____| ^ |__COLOR BURST 3.579545MHZ < > 750ns breezeway <-------> 4.85us Back porch <---> 4.71us Horz Sync < > 1.54 front porch <---------------> Horizontal blanking 11.1us <--52.4us video information-...--> TIME-BASE CORRECTOR In VRC takes the incoming video signal, strips sync from it, remixes it with a new set of sync signals. line by line, and the original sync is just used as a trigger to mark the correct position on the line for injecting the new syn MP3 files CD stores music using 44,100 samples per second, 16 bits per sample and two channels 10 million bytes of data per minute of music three minute song requires 30 megabytes of data. MPEG acronym for Moving Picture Experts Group. developed compression systems used DVD movies, HDTV broadcasts and DSS satellite systems use MPEG compression includes a subsystem to compress sound, called MPEG audio Layer-3. abreviation - MP3. MP3 compress a song by a factor of 10 or 12 retain CD Cathode Ray Tube Almost all TVs in use today rely CRT, to display images cathode ray tube, "cathode" is a heated filament (not unlike the filament in a normal light bulb). vacuum created inside a glass "tube." "ray" is a stream of electrons that naturally pour off a heated cathode into vacuum. anode is positive,attracts electrons off of cathode. electrons is focused by focusing anode into a tight beam and then accelerated by an accelerating anode. hits flat screen at the other end of tube. screen is coated with phosphor, which glows when struck steering coils are simply copper windings create magnetic fields inside the tube, One set of coils moves the electron beam vertically, another set moves the beam horizontally. black-and-white TV, screen is coated with white phosphor move electron beam in a "raster scan" pattern across and down the screen. one line across the screen from left to right. I then quickly flies back to the left side, All TVs use interlacing technique when painting screen. screen is painted 60 times per second but only half lines are painted per frame. beam paints every other line as it moves down the screen, example every odd-numbered line. next time it it paints even-numbered lines, entire screen, two passes, painted 30 times per second. alternative to interlacing called progressive scanning, which paints every line on screen 60 times a second. Most computer monitors use progressive scanning because it significantly reduces flicker. Because electron beam is painting all 525 lines 30 times per second,paints 15,750 lines per second. (Some people can actually hear this frequency The horizontal retrace signals are five microsecond pulses at zero volts. signal varying wave between 0.5 volts and 2.0 volts, 0.5 volts representing black, 2 volts representing white. This signal drives intensity circuit for the electron beam. In a black-and-whiteTV this signal can consume about 3.5 MHz of bandwidth, while in a color set the limit is about 3.0 MHz. A vertical retrace pulse is similar to a horizontal retrace pulse but is 400 to 500 microseconds long. vertical retrace pulse is serrated with horizontal retrace pulses in order to keep the horizontal retrace circuit in the TV synchronized. color TV signal starts off like a black-and-white signal. extra chrominance signal is superimposing a 3.579545 MHz sine wave onto the standard black-and-white signal. Right after horizontal sync pulse, eight cycles of a 3.579545 MHz sine wave are added as a color burst. Following eight cycles, phase shift in chrominance signal indicates color to display amplitude of signal determines saturation.following table shows you the relationship between color and phase: Color Phase Burst 0 degrees Yellow 15 degrees Red 75 degrees Magenta 135 degrees Blue 195 degrees Cyan 255 degrees Green 315 degrees standard NTSC analog waveforms requires 4 MHz bandwidth. add in sound,something called vestigial sideband and a little buffer space, TV signal requires 6 MHz bandwidth. FCC allocated three bands of frequencies in radio spectrum chopped into 6 MHz slices to accommodate TV channels: 54 to 88 MHz for channels 2 to 6 174 to 216 MHz for channels 7 through 13 470 to 890 MHz for UHF channels 14 through 83 composite TV signal described in the previous sections can be broadcast to your house on any available channel. composite video signal is amplitude modulated into appropriate frequency, and then the sound is frequency modulated (+/- 25 KHz) as a separate signal, typical VGA pinout: pin 1 - Red video pin 2 - Green video pin 3 - Blue video pin 4 - Ground pin 5 - Self test pin 6 - Red ground pin 7 - Green ground pin 8 - Blue ground pin 9 - No pin pin 10 - Digital ground pin 11 - Reserved pin 12 - Reserved pin 13 - Horizontal sync pin 14 - Vertical sync pin 15 - Reserved PAL and NTSC timing information Horizonal Timing PAL NTSC A (us) 64 B (us) 4.7+-0.2 4.7+-0.1 C (us) ? 1.4 D (us) 52 E (us) 12 Horiz. Frequency (Hz) 15625 15734.2 Subcarr. frequency (MHz) 4.43 3.579545 Subcarr. cycles per line ? 227.5 XXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXX_ _W__XXXXXXXXXXXXXXXXXXXXXX_ _W_XXXXX |_| VIDEO |_| |B| |---------D----------|C| |----E---| |--------------A--------------| Vertical Timing PAL Vertical frequency(Hz) 50 59.94 Blanking (lines) 25-37 Active lines 482-486 Total lines 625 525 Equalization pulses 3+3+3 O (scanlines) 312.5 262.5 P (ms) Q (ms) R (scanlines) 241-243 S (ms) XXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXX_ ___XXXXXXXXXXXXXXXXXXXXXX_ __XXXXX |_| VIDEO |_| |P|-Q-|---------R----------|S| |---T--| |--------------O-------------| Horizonal Timing PAL NTSC A (us) 64 B (us) 4.7+-0.2 4.7+-0.1 C (us) ? 1.4 D (us) 52 E (us) 12 Horiz. Frequency (Hz) 15625 15734.2 Subcarr. frequency (MHz) 4.43 3.579545 Subcarr. cycles per line ? 227.5 XXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXX_ _W__XXXXXXXXXXXXXXXXXXXXXX_ _W_XXXXX |_| VIDEO |_| |B| |---------D----------|C| |----E---| |--------------A--------------| Vertical Timing PAL Vertical frequency(Hz) 50 59.94 Blanking (lines) 25-37 Active lines 482-486 Total lines 625 525 Equalization pulses 3+3+3 O (scanlines) 312.5 262.5 P (ms) Q (ms) R (scanlines) 241-243 S (ms) XXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXX_ ___XXXXXXXXXXXXXXXXXXXXXX_ __XXXXX |_| VIDEO |_| |P|-Q-|---------R----------|S| |---T--| |--------------O-------------| Published by ELH Communications Ltd. all rights reserved. Circuits [ index ][ back ][ site search ] [ acronyms ] [ discussion ] [ mail to a friend ] [ post message ] PAL and NTSC timing information Horizonal Timing PAL NTSC A (us) 64 B (us) 4.7+-0.2 4.7+-0.1 C (us) ? 1.4 D (us) 52 E (us) 12 Horiz. Frequency (Hz) 15625 15734.2 Subcarr. frequency (MHz) 4.43 3.579545 Subcarr. cycles per line ? 227.5 XXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXX_ _W__XXXXXXXXXXXXXXXXXXXXXX_ _W_XXXXX |_| VIDEO |_| |B| |---------D----------|C| |----E---| |--------------A--------------| Vertical Timing PAL Vertical frequency(Hz) 50 59.94 Blanking (lines) 25-37 Active lines 482-486 Total lines 625 525 Equalization pulses 3+3+3 O (scanlines) 312.5 262.5 P (ms) Q (ms) R (scanlines) 241-243 S (ms) XXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXX_ ___XXXXXXXXXXXXXXXXXXXXXX_ __XXXXX |_| VIDEO |_| |P|-Q-|---------R----------|S| |---T--| |--------------O-------------| Video signal levels Video signals used in TV production For all standard TV video signal systems the standard video level was 1 V p-p in 75 ohms, for video + sync. However, waveform monitors were marked in 140 "IRE units", 40 for sync, and 100 for video. Under the original RS-170 standard, video was 1.4 Vp-p, with the white level 1.0V up from blank (which is the reference) and the sync tip 0.4V down (negative) with respect to the same reference level. And from blank to white was 100 IRE units. The RS-170 levels have pretty much been replaced in most applications by the later RS-343 standard levels. Under this standard, the entire signal (including the sync pulses) was reduced to 1.0 Vp-p across 75 ohms. However, the same 100/40 division above and below the blank level was retained. This results in the reference white level being 0.714 V positive from blank, and the sync tips 0.286 V negative from blank. The BLACK level, under this standard, is slightly up from blank, having an 0.054V "setup" or "pedestal". Standard practice in Europe has also been to use a 1.0V p-p signal, but they simplified life and set white to +0.700V and sync to -0.300V, again with respect to the blanking level, and did away with "setup" (i.e., black and blank are the same level). PC video levels From European 1 Vpp system we got one common PC video standard, which uses 0.700V p-p video (with separate syncs). Unfortunately, we also saw the development of ANOTHER common PC video practice, which was to simply use RS-343 with the setup chopped out - resulting in 0.660V p-p for the video. Compatability issues All of these are close enough to work about equally well on most equipment and monitors, but there are several "standards" for video floating around. ePanorama.net - Ground Loops S-video to composite video adapter convert Y/C video (S-video) to composite video. works with both PAL and NTSC video standards. Y-ground------------------+ +---------- RCA/composite ground C-ground------------------+ Y-------------------------+ +--------- RCA/composite video C------------||-----------+ 470pF circuit can be quite easily build inside a S-video connector case if a physically small size 470 pF (ceramic) capacitor is used.Larger capacitor values also work, but cause picture to become"softer". voltage rating of capacitor can be 10V or more. This circuit works in practice quite well even though circuit operation is not ideal. impedances and signal levels not matched exactly right, but near enough to work accetably. picture quality you get from this circuit is is good, but not as good as with best possible composite video output circuitry. Here is pinout of S-video connector shown from end with FEMALE PINS (picture is a view on equipment back/front panel): 1 Y ground 2 C ground 3 Y (luminance+sync) 4 C (crominance) 7-pin S-video What if my PC graphics card has 7-pin S-video connector four pin S-video connector as shown above is standard connector for carrying S-video. Those seven pin connectors seen on some PC graphics cards are non-standard connectors for carrying S-video. use of pins on those seven pin connectors is not standardized and can vary from manufacturer Generally four pins on those 7-pin connectors on same places as standard four pin S-video connector other three pins can have then some extra signals not part of S-video (usually some pins of those carry composite video and some control signals, in opposite way have a composite video signal want to feed to S-video circuit sort of work also in this way. If you connect a comoisute video source to S-video input of your TV using this circuit, picture quality will be worse than if using real composite vidoe input of your TV. reason for this is that after circuit color information is still in brighness signal, see some interference on screen caused by color subcarrier which gets to screen. Closed-Caption Decoder http://www.southernnetcom/auditech Since 1993, television sets with screens of 13 inches or more that are sold in the United States must have built-in decoders,under Television Decoder Circuitry Act. Set-top decoders are available, too, for older TV sets. captions hidden in line 21 data area found in vertical blanking interval of television signal. Line 21 is the line in the vertical blanking interval that has been assigned to captioning (as well as time and V-chip information). Each frame video transmit two characters of captioning (or special commands that control color, popups, etc.) VCR Plus Decoded http://www.tinaja.coml third /vcrplus.pdf copy-protected VHS tapes - TOSHIBA case of making them sensative to adapt to varying TV conditions city is likely to get a stronger signal than > on in a remote mountain village. why AGC's were introduced. it made macrovision possible as it could fool AGC. 1. RF-AGC which compensates for different signal strength at aerial, it measures RF amplitude and is *not* sensitive to video contents because with negative modulation the sync is the peak and isconstant, this AGC will not work on CVBS (baseband video) inputs. 2. Video-AGC which normalizes baseband signals which enter *after* tuner-IF. A.o. this compensates for different signal strengths when you connect two VCRs together. It measures peak-white, so it *is* sensitive to video content and thus to Macrovision pulses. a television does NOT have a video-AGC, unless you want to call beam current limiter circuits an AGC. (Exception: the Secam-L system with positive modulation requires an RF-AGC which measures peak-white instead of peak-sync.) > Same reason some TV's are susceptable, as the AGC in the amplifier stage > gets misled and boosts or cuts the signal accordingly. No, the RF-AGC does not see the peak-white of the anti-copy pulses. If you connect the VCR to the TV via the CVBS (baseband) input, then the RF-AGC is not even in the path. Still, it may be disturbed. But the sync separator may see the extra inserted Hsync pulses, and due to the phase disturbance the video clamping may be disturbed too. Hope I've cleared this up a little more. (Did I ???) Have had some sleepless nights over Macrovision too ... Original Subject: Re: Synchronous Detection In article , rtorgerson@electriciti.com' says... > >I have a application were I am sending out a test signal and I receive back a >response that is 2 to 100f the signal that is sent out. The common mode >noise can be ten times my test signal. If common-mode noise is the only problem, why don't you make life simple for yourself and use balanced transmission. Works great for IEEE 10base-t (10 MBPS ethernet on twisted pair). >The one problem I have is that I want to >set the test signal as large as I can without distortion. The way I was going >to do this was by measuring both the fundamental and the second harmonic. When >the second harmonic is 50f the fundamental I would reduce the test signal. This is confusing. Why can't you just measure the harmonic distortion vs. output power, and then set the transmitting device at a reasonable level? Or is your load generating harmonics that depend on the TX level? >Does any one know of any good references for Synchronous Detection? And is >it possible to measure both the fundamental and a second harmonic with Synchronous >Detection? The advantage of synchronous detection is that it's a linear process and can minimize the receiving bandwidth. You can achieve it by either transmitting a pilot tone with your signal, or recovering a synchronous reference by some form of phase locked loop operating on the received signal. If your signal has very narrow bandwidth but with long term frequency drift, synchronous detection will permit you to use a very narrow recovery bandwidth. A phaselocked loop is in fact a synchronous detector. An example of effective synchronous detection is the 3.58 MHz color burst subcarrier loop in a TV set. It's locked to the master oscillator at the station to give you a perfect color rendition of Roseanne's face. -- = ======================HIGH_FREQ================================== ------------------------------------------------------------- Frequency SPECTRUM 0 Hertz Steady direct current 50-60 Hertz AC power (5000Km) ----------------------USA--------------------------- 16-16.000 kHz Audio frequencies 10-30 kHz v.l.f -very low frequency (30-10Km) 30kHz to 30 MHz Radio Frequencies 30-300 kHz l.f. low frequency (10-1Km) 30S35 kHz Marine com & navigation, aero nav. 300-3000 kHz m.f medium frequencies (1000-100m) 535-1605 kHz AM broadcast bands 1800-2000 kHz 160 meter band ----------------------Football_Field--------------------------- 3-30 MHz h.f. - high frequencies (100-10m) 3.5-4 MHz 80 me1erband 7-7.3 MHz 40 band 14-14.35 Mnl 20 meter band 21-21.45 MHz 15meterbend 26.85-27.54 MHz Industrial, Scientific, medical 28-29.7 MHz 10 meterband 26.86-27.455 MHz Citizens Band Class D ----------------------Human----------------------------------- 30-300 MHz very high frequencies (1O-1m) 30-50 MHz Police,fire,highway,railroad 50-54 MHz 6 meter band 54-72 MHz TV channels 2 to 4 72-76 MHz Government, Aero,Marker 75MHz 76-88 MHz TV channels 5 and 6 88-108 MHz FM broadcast band 108-118 MHz Aeronautical navigation 118-136 MHz Civil Communication Band 148-174 MHz Government 144-148 MHz 2 meter band 174-216 MHz TV channels 7 to 13 216-470 MHz Amateur, government. CB Bend non-govemment, fixed or mobile aeronautical navigation 220-225 MHz Amateur band. 1-1/4 meter 225-400 MHz Military 420-450 MHZ Amateur band, 0.7 meter 462.5-465 MHz Citizens Band 300-3000 MHz u.h.f. - ultra high frequencies (lOO-1Ocm) 470-890 MHz TV channels 14 to 83 890-3000 MHz Aero navigation, amateur bands. Qovernment& non-government, fixed and mobile 1300-1600 MHz Radar band 3000-30,000 MHz s.h.f. - super high frequencies (10-1cm) Government and non-govetnment, amateur bands, radio navigation ----------------------Grain_OF_SAND------------------------------- 30 to 300 GHz Extra-high frequencies (weather (1-0.1cm) radar, experimental, government) ----------------------Bacterium------------------------------- 30-0.7 um Infrared light and heat 0.76-0.39 um Visiblelight (300teraHz) 6470-7000 angstroms Red light 5850-6740 angstroms Orange light 5750 5850 angstroms Yellow light 5560-5750 angstroms Maximum visibility 4912-5560 angstroms Green light 4240-4912 angstroms Blue light 4000-4240 angstroms Violet light ----------------------Virus------------------------------- 0.390-0.032 um Ultraviolet light (30petaHz) 3200-1 angstroms X-rays 1-0.06 angstroms Gamma rays ----------------------Atom------------------------------- 0.0005 angstroms Cosmic rays ----------------------Atomic_Nucleus------------------------------- 1um micrometer(10^-6m) GHz gigahertz(10^9 Hz) 1 angstrom = 10^-10 meters ------------------------------------------------------------- 510 -535 Misc Radio beacons 500 KHz Distress(CW) ship to shore 415-490KHz Maritime mobile (CW) ship to shore 285-400KHz Radio beacons,weather weath,AM, carrierCurrent_60Hz_trans aeronautical and marine 190-285KHz Radio beacons,weather weath,AM, carrierCurrent_60Hz_trans european long wave broadca 160-190KHz Fixed Public,license-free exper 1W , no need licen experiimental european long wave broadcast fixed(point to point) 110-160KHz maritime mobile, noisy, some RTTY trans lowest freq long wave broadcast fixed(point to point) 90-110KHz Loran Navigation 30-90KHz fixed,mobile RTTY trans, some CW , noisy standard freq /time sign 14-30KHz submarine comunications RTTY trans, some CW , noisy VLF wold wide hig-power miltary and commercial 10-14KHz atm phenomena, whistlers lowest radio sprect freq used omega signals freq standard below 10KHz atmoshper noise whistlers experimental experiment trans miltary ------------------------------------------------------------- 535-1635 KHz AM 44-49 Mhz Analog cordless phone 54-88 Mhz TV chaneel 2-6 (VHF) 88-108 MHz FM 174-216 Mhz TV channel 7-13MHz (VHF) 470-806 MHz TV Channel 14-69 (UHF) 800 MHz RF wireless modems 806-890 MHz Cellular Phones 900 MHz digital cordless phones 900-929 Mhz Personal Communication services (PCS) 929-932 Mhz Nation wide pagers 932-940 MHz two-way pagers 1610-1626.25 MHz Satellite phones uplink 1850-2200 MHz Future PCS 2483.5-2500 MHz Satellite phones downink 4-6 Ghz Satellite TV large dish 11.7-12.7 Ghz Satellite TV small dish 28-29 GHz Wireless "cable" TV ------------------------------------------------------------- Frequency SPECTRUM 0 Hertz Steady direct current 50-60 Hetz AC power ----------------------USA--------------------------------- 16-16.000 kHz Audio frequencies 5000Km 10-30 kHz v.l.f -very low frequency 30-10Km 30 kHz - 30 MHz Radio Frequencies 30-300 kHz l.f. low frequency 10-1Km 30S35 kHz Marine com & navigation, aero nav. 300-3000 kHz m.f medium frequencies 1000-100m 535-1605 kHz AM broadcast bands 1800-2000 kHz 60 meter band ----------------------Football_Field--------------------------- 3-30 MHz h.f. - high frequencies 100-10m 3.5-4 MHz 80 me1erband 7-7.3 MHz 40 band 14-14.35 Mnl 20 meter band 21-21.45 MHz 15meterbend 26.85-27.54 MHz Industrial, Scientific, medical 28-29.7 MHz 10 meterband 26.86-27.455 MHz Citizens Band Class D ----------------------Human----------------------------------- 30-300 MHz very high frequencies 1O-1m 30-50 MHz Police,fire,highway,railroad 50-54 MHz 6 meter band 54-72 MHz TV channels 2 to 4 72-76 MHz Government, Aero,Marker 75MHz 76-88 MHz TV channels 5 and 6 88-108 MHz FM broadcast band 108-118 MHz Aeronautical navigation 118-136 MHz Civil Communication Band 148-174 MHz Government 144-148 MHz 2 meter band 174-216 MHz TV channels 7 to 13 216-470 MHz Amateur, government. CB Bend non-govemment, fixed or mobile aeronautical navigation 220-225 MHz Amateur band. 1-1/4 meter 225-400 MHz Military 420-450 MHZ Amateur band, 0.7 meter 462.5-465 MHz Citizens Band 300-3000 MHz u.h.f. - ultra high frequencies lOO-1Ocm 470-890 MHz TV channels 14 to 83 890-3000 MHz Aero navigation, amateur bands. Qovernment& non-government, fixed and mobile 1300-1600 MHz Radar band 3000-30,000 MHz s.h.f. - super high frequencies 10-1cm Government and non-govetnment, amateur bands, radio navigation ----------------------Grain_OF_SAND------------------------------- 30 to 300 GHz Extra-high frequencies (weather radar, experimental, government) 1-0.1cm ----------------------Bacterium------------------------------- 30-0.7um Infrared light and heat 0.76-0.39 um Visiblelight 300teraHz 6470-7000 angstroms Red light 5850-6740 angstroms Orange light 5750 5850 angstroms Yellow light 5560-5750 angstroms Maximum visibility 4912-5560 angstroms Green light 4240-4912 angstroms Blue light 4000-4240 angstroms Violet light ----------------------Virus------------------------------- 0.390-0.032um Ultraviolet light 30petaHz 3200-1 angstroms X-rays 1-0.06 angstroms Gamma rays ----------------------Atom------------------------------- 0.0005 angstroms Cosmic rays ----------------------Atomic_Nucleus------------------------------- 1um micrometer(10^-6m) GHz gigahertz(10^9 Hz) angstrom 10^-10 meters ------------------------------------------------------------- RADIO ALPHABET Letter Word pronunciation A Alfa Al Fah B Bravo Bra Voh C Charlie Char Lee D Delta Del Tah E Echo Ek Oh F Foxtrot Foks Trd G Golf Golf H Hotel Ho Tell I India In Dee Ah J Juliett Jew Lee Ett K Kilo Key Loh L Lima Lee Mah M Mike Mike N November No Vem Bar O Oscar Oss Cahr P Papa Pah Pah Q Ouebec Ke Beck R Romeo Row Me Oh S Sierra See Air Rah T Tango Tang Go U Uniform You Nee Form V Victor Vick Tar W Whiskey Wiss Key X X-Ray Ecks Ray Y Yankee Yang Kee Z Zulu Zoo Loo ------------------------------------------------------------- MORSE CODE Later Code Letter Code b A .- Q --.- 1 .--- B -... R .-. 2 ..-- C -.-. S ... 3 ...- D -.. T 4 .... E . U ..- 5 ..... F ..-. V ...- 6 -.... G --. W .-- 7 --... H .... X -..- 8 ---.. I .. Y -.-- 9 ----. J .--- Z --.. O ---- K -.- Error ....... . .-.-.- L .-.. wait .-... : --..-- M -- End Msg - -... ; N -. EndWrk ...-.- 0 --- InvXmit-.p ( -.--.- P .--. / -..-. ======================ELECT_HIGHFREQ========================== RF/DIGITAL NOISE REDUCTION Old joke DC to light LF electronics.. had, inductor,resistors, transistors 1) have a schematic. just hook it up 2) watch for gross error, supply bypasses, groundloops 3) all signal on wires RF electronics..TV /Radio 1) arrangement of schematic components sensitive 2) antennas, crosstalk, trans lines, impedance matching 3) semi blackmagic, some signal as invisible RF energy 4) pc board important as schematic (add to datasheet) Microwave eletronics.. 1) wave guides, smith charts, impedance matching 2) Real black magic, in terms of invisible RF energy 3) arangement of everything is the shematic space = critical component / / / / /_________/ / | /^ E | / | / | ->H | / |/________|/ Light electronic... 1) Wave guides have become fiber optics 2) RF energy now visible again. -----------------------LF_ELECTRONICS----------------------- ______________ | |__| | ___| |___ |___| 1 VCC 14 |___|______ | | | .22uF ___| |___ _|_ |___| 2 13 |___| ___ | | | ___| |___ _|_ |___| 3 12 |___| /// | | ___| |___ |___| 4 11 |___| | | ___| |___ Typical Digital |___| 5 10 |___| Supply Bypass | | ___| |___ |___| 6 9 |___| | | ___| |___ ___|___| 7 GND 8 |___| | | | _|_ |______________| /// For low frequencies the general rules are... 1) Supply bypass capacitors 2) Short leads 3) The greater the distance, the less the stray C 4) Watch for cross talk...etc __\_ H | / | _______________|_____________ ()_____________\|/____________) R_cm --> I | V L_cm |_/_ \ SELF INDUCTANCE (uH) for ROUND WIRE (L_cm,R_cm) L_uH=.002*L_cm*( ln(2*L_cm/R_cm) -.75 ) __-----__ / d_inch \ Impedances inside coax / ___ \ | / ^ \ | | | |_ |__\| \ \___/ // \ D_inch/ \__ __/ ----- Z_ohms = sqrt(L/C) = 138*log(D_inch/d_inch)/sqrt(E) C_pf/ft = 7.36*E/log(D_inch/d_inch) L_uH/ft = 0.14*log(D_inch/d_inch)) Delay_ns/ft = 1.016*sqrt(E) Propagation_%_c = 100/sqrt(E) CutOffFreq_Ghz =7.5/( sqrt(E)*(D_inch+d_inch) ) Dielectric Constant E TFE 2.1 ethylene propylene 2.24 polyethylene 2.3 cellular polyethylene 1.4-2.1 silicone rubber 2.08-3.5 polyvinylchoride 3-8 ======================RF_ELECTRONICS====================== When entering the RF world, you begin to see that having short leads on supply bypass capacitor is not telling you the whole story. good way to see to is measure impedance of a 0.22uf bypass capacitor over frequency. IMPEDANCE OF 0.1uF CAPACITOR 10 |..C............................................. | C . . . L . | C . . L . | C . L . . | C. . L . . | C . L . . 1 |..............C...........L..................... | . C .L . . | . C L . . | . C L. . . | . R . . . | . . . . .1 |................................................ | . . . | . . . . | . . . . | . . . . | . . . . |______________________________________________ . 100KHz 1MHz 10MHz 100MHz 1GHz above 10MHz, you really don't have capacitor. self inductance takes over, and digital supply current spikes really seeing a "bypass inductor" The RF guys have long known this. they never use things like 0.22uf capacitors any where critical like to use those silver-mica capacitors in picoFarads. ^ VCC 0.1uF /_\ Internal prop delays for a CS80CBI _______|______ inverter typ below 100pS. | => I | _____ _|_ _||<- | ___ __ | || /|\ Vout | |_ | ||__ ___| | ___| |__ =>I | _|_ | __| |______ ... | /Vin\ | || _|_ | \___/ |_|| ___ | | ||-> ______|__ ... |_____|_________| I<= <= I _|_ /// current always flows in loops. Say you have an inverter swinging from low to high. Current coming out of inverter to charge the stray C. inverter get this current from the supply bypass. current will form the loop shown above. _______\_____ I <--- | / | ____________|____ | | \ | _____ /|\ \ \|/ H Field \ | __\__ | \ | _____ | Magnetic Radiation \ | \ | \ ---> I \ | \____________\ | | | |______/______| \ in terms of how much magnetic field does current spike loop generate to understand size of the "bypass inductor" . inductance of loop wire can show the inductance is related to loop area. _ _ Dia_inch | | | | _| | | |_ / __| |__ \ / / ^ \ \ R_inch/Dia_inch > 2.5 / / /|\ \ \ | | | | | | | R_inch | | \ \ / / \ \__ __/ / \_ --- _/ ------- SELF INDUCTANCE (uH) for a RING OF WIRE (R_cm, Dia_inch) L_uH (R_inch/100)*( 7.353*log(16*R_inch/Dia_inch) -6.386) area of the loop which defines the size of the inductance. when you make the loop area small? ___\__ --> I ______|___/__|________________ ->()___________\|/______________ | |_/____| _/___ | | ________\_______|_\___|_____| | <-()_____________________|_______| <-- I |___\_| __ / | |__ _____ |__| | | | |*() () | | \_/\_/\_/ L1 | Lb M _ _ _ | Lb = L1 + L2 -2*M /*\/ \/ \ L2 | if L1 = L2 =M __ | () () | | | |__| |_____| then Lb=0 |__| When return path flow right next to each other, mutual inductance cancel out self inductance. Remember the short lead rule? Suppose don't make bypass capacitor leads short, rather just make return current flow next to any signal current. ( make Loop area is small) _____________________________ ->()____________________________) <- d_cm | D_cm Z_ohms sqrt(L/C) | _____________________________ ->()____________________________) L_cm C_pf/meter = 12.06/log(2*D_cm/d_cm) L_uH/meter = 0.92*log(2*D_cm/d_cm) Z_ohms = 276*log(2*D_cm/d_cm) now a transmission line. current loop will still generate a magnetic field. magnetic field is completely confined in space between conductors. A transmission line just like microwave wave guide. have current, voltage, E fields and H fields. are happening all together in a small area of space Voltage dropping current \ -----> \ \____\ \______\ \ \ \ \ \ \ _ \ _ ->E \| \ \ _ \| \ \|/ _ /_ \ ^ _ /_ v H |_/ \ _V Voltage \ |_/ \ __/_ \ Pulse \ __/_ |_/ \ \ \ |_/ \ | _V | voltage \ \ - + \ \____\ \______\ \ \ \ \ \ ---> \ _ \ _ | E \| \ \ _ \| \ \|/ _ /_ \ ^ _ /_ v H |_/ \ _V \ |_/ \ __/_ \ __/_ ->E |_/ \ \ |_/ \ \|/ | | v H \ \ \ \____\ \______\ \ \ \ \ current <------ Voltage increasing Between conductors, capacitance. a fast voltage pulse, transmission line form current loops within itself. confine both the E field and H field completely between conductors. So now signal really both voltage and current and electromagnetic wave, in same place. if signal current is differential (twisted pair lines), transmission line will look like no signal at short distance away. If only air bewteen conductors, this wave will travel at speed of light. ( 1ns =about 1foot) _____________________________ ->()____________________________) <- d_cm | D_cm Z_ohms sqrt(L/C) | _____________________________ ->()____________________________) L_cm C_pf/meter = 12.06/log(2*D_cm/d_cm) L_uH/meter = 0.92*log(2*D_cm/d_cm) Z_ohms = 276*log(2*D_cm/d_cm) Z_air =377 ohms Rabbit ears 300 ohm Transmission line of rabbit ears follow equation. Transmission lines have resistance impedances. violate short lead supply bypass capacitor rule and connect 5 ohm transmission line between IC and supply bypass as shown below,now be bypassing your supply with 5 ohm resistor all frequencies 10MHz ___\__ --> I ______|___/__|______________ 5 Ohm ->()___________\|/_____________|__/\ __ |_/____| _/___ \/ | ________\_______|_\___|_____ _|_ <-()_____________________|_____|_ ___ Bypass <-- I |___\_| |______| 0.22uF In terms of a PC board layout is is common to have a signal wire over ground plane with small enough dielectric between. recommended spacings result in 50ohm trans line _ I signal current /| / / / / /_____/ / / / |_____|/ / / / /_________________/ / |/_ I return path |_________________|/ simply laying out PC boardthat all signal current runs next to return path, easy to have all high frequency circuitry see nothing but transmission lines. ^ VCC 0.1uF /_\ Internal prop delaysCS80CBI _______|______ inverter typically below 100pS. | => I | _____ _|_ _||<- | ___ __ | || /|\ Vout | |_ | ||__ ___| Signal Current Sees | ___| |__ Minimum Inductance | _|_ | __| | | /Vin\ | || | =>I ___________... | \___/ |_|| |_____| | | ||-> ________| Any Type of tran line |_____|_________| I<= |___________... <= I _|_ /// THIS IS WELL WORTH THE EFFORT. 1) High frequency energy completely confined a) This greatly reduces crosstalk Low RF radiation both in and out. b) Signals travel faster (No Inductors) speed light Efficient use of signal energy 2) termination ( Impedance at end =same as transmission Z) a) Keeps the ringing down. costto know where all signal current flows and simply provide a path of least inductance (Path of least indcutance = min loop area) Supply bypass ____________ 0.1uF | | _______| |_________________ _|_ |___| 1 6 |___| __________ 50_Ohms ___ VCC | SOT6 | CS | ______|_______| |_______\__________ | _|_ |___| 2 5 |___| /__________ 50_Ohms _|_ ___ GND | | DOUT | \ / |_________| |_______\__________ V Local | |___| 3 4 |___| /__________ 50_Ohms Gnd | VIN | | CLK | _ | |____________| _|_ | |_/\ ___| adcv0831 \ / Local |_| \/ V Gnd use of this principle involved the building of first SOT23-6 tester for an ADC as is shown. In this case, the challenges were.. A) no separate analog and digital ground.ran out of pins B) 3 foot cables connect the Eagle tester to the SOT23-6 handler. A standard cable size is 50 ohms change thinking for TD using outer shield connector as current return paths, In the RF world, if you can't transmit, you also can't receive. tansmission line mentality introduces Electromagnetic shielding as well as Electrostatic shielding. Travelling wave string on tension tension s mass_per_unit u velocity sqrt(tension/mass_per_unit) ------------------------------------------------------------- H ^ /|\- | - |______\ E \ /- \ - \ - - \ - \ E /______\ -\ |\ - | \ -\|/ \ V H \- _\| S Electrical c =sqrt(1/(e0*u0)) phi=u0*H eo*E Z = E/H = sqrt(u0/e0) = 377ohms ------------------------------------------------------------- Maxwell's Equations __ \/ dot J = -delta_rho/dt __ \/ cross E = -delta_B/dt V=delta_Phi/dt __ \/ cross H = J+ delta_D/dt H =I*N __ \/ dot D = rho __ \/ dot B = 0 -----------------------SUPPLY_BY_PASS----------------------- ______________ | |__| | ___| |___ |___| 1 VCC 14 |___|______ | | | .1uF ___| |___ _|_ |___| 2 13 |___| ___ | | | ___| |___ _|_ |___| 3 12 |___| /// | | ___| |___ |___| 4 11 |___| | | ___| |___ |___| 5 10 |___| | | ___| |___ |___| 6 9 |___| | | ___| |___ ___|___| 7 GND 8 |___| | | | _|_ |______________| /// world of supply supply bypass decoupling has been changing due to the ever higher and higher speeds at which digital circuit can now operate. A standard off_the_shelf digital circuit with its supply by_pass is shown above. At speeds which digital circuits using CS80CBI process at, this 0.1uF capacitor really is not a capacitor. SELF INDUCTANCE (uH) for ROUND WIRE (L_cm,R_cm) __\_ H | / | _______________|_____________ ()_____________\|/____________) R_cm --> I | V L_cm |_/_ \ L_uH=.002*L_cm*( ln(2*L_cm/R_cm) -.75 ) Inductances in the nanoHenry range are not hard to come by given the package lead sizes. equation for single wire inductance is give above. IMPEDANCE OF 0.1uF CAPACITOR 10 |..C............................................. | C . . . L . | C . . L . | C . L . . | C. . L . . | C . L . . 1 |..............C...........L..................... | . C .L . . | . C L . . | . C L. . . | . R . . . | . . . . .1 |................................................ | . . . | . . . . | . . . . | . . . . | . . . . |______________________________________________ . 100KHz 1MHz 10MHz 100MHz 1GHz The 0.1uF supply bypass capacitance may have the impedance as is shown above. Above a certain frequency, the size of the capacitor no longer matters. Rather, it is how the capacitor is connected that defines the impedances. _______\_____ I <--- | / | ____________|____ | | \ | _____ /|\ \ \|/ H Field \ | __\__ | \ | _____ | Magnetic Radiation \ | \ | \ ---> I \ | \____________\ | | | |______/______| \ Current really always flows in loops. Wher current flows, a magnetic field. However it is the Area which current loop encircles determins how much magnetic field gets radiated. To have inductor, you need space for magnetic field. Little space, little magnetic field and inductance. SELF INDUCTANCE (uH) for a RING OF WIRE (R_cm, Dia_inch) _ _ Dia_inch | | | | _| | | |_ / __| |__ \ / / ^ \ \ R_inch/Dia_inch > 2.5 / / /|\ \ \ | | | | | | | R_inch | | \ \ / / \ \__ __/ / \_ --- _/ ------- L_uH (R_inch/100)*( 7.353*log(16*R_inch/Dia_inch) -6.386) equations of inductance for a ring of wire is given above. If current loop is made to runthat currents flowing in opposite directions are next to each other, you get a transmission line. ___\__ --> I _______ ______|___/__|______________| | ->()___________\|/_____________| | |_/____| _/___ |50Ohms | ________\_______|_\___|_____| | <-()_____________________|_____| | <-- I |___\_| |_______| / From outside world, transmission lines have magnetic fields cancelling out. In terms loop current, impedances look like a resistor. Depending on spacing of the wires,it is common to set this resistance value to be typically 50 ohms. Without inductance, the moment you apply signal voltage, you instantly get signal current. Things happen close to speed of light. Voltage dropping current \ -----> \ \____\ \______\ \ \ \ \ \ \ _ \ _ ->E \| \ \ _ \| \ \|/ _ /_ \ ^ _ /_ v H |_/ \ _V Voltage \ |_/ \ __/_ \ Pulse \ __/_ |_/ \ \ \ |_/ \ | _V | voltage \ \ - + \ \____\ \______\ \ \ \ \ \ ---> \ _ \ _ | E \| \ \ _ \| \ \|/ _ /_ \ ^ _ /_ v H |_/ \ _V \ |_/ \ __/_ \ __/_ ->E |_/ \ \ |_/ \ \|/ | | v H \ \ \ \____\ \______\ \ \ \ \ current <------ Voltage increasing w0=sqrt(L*C) = sqrt(dL*dC*X^2) =X*sqrt(dL*dC) velocity=(2*pi()/sqrt(dL*dC) transmission linethought of as a "wave_guide". E and H field travel down the such the E field is set by signal voltage and H field is set by signal current.Given transmission line typically 50 ohms, power, voltage, current, etc are all defined. Using a transmission line really win/win situation. you remove inductance from equation which greatly speeds things up. also prevent electromagnetic radiation leaving or entering circuit. you confine the signal energy to flow where you want, everything gets better. ^ VCC 0.1uF /_\ Internal prop delays for a CS80CBI _______|______ inverter typically typically 100pS | => I | _____ _|_ _||<- | ___ __ | || /|\ Vout | |_ | ||__ ___| Signal Current Sees | ___| |__ Minimum Inductance | _|_ | __| | | /Vin\ | || | =>I ___________... | \___/ |_|| |_____| | | ||-> ________| Any Type of trans line |_____|_________| I<= |___________... <= I _|_ /// Inside chip, things can now happen very fast. prop delays for inverter CS80CBI typically under 100 picoseconds! 10GHz bandwidth. If digital circuit is connected to outside world shown above, current loop can be confined in space consisting of transmission line and supply bypass capacitor. to make this whole path look real in impedances by having currents flowing in opposite directions next to each other so that their magnetic fields cancel out. Another way say it to make lead lengths of bypass capacitor as short as possible. Supply bypass ____________ 0.1uF | | _______| |_________________ _|_ |___| 1 6 |___| __________ 50_Ohms ___ VCC | SOT6 | CS | ______|_______| |_______\__________ | _|_ |___| 2 5 |___| /__________ 50_Ohms _|_ ___ GND | | DOUT | \ / |_________| |_______\__________ V Local | |___| 3 4 |___| /__________ 50_Ohms Gnd | VIN | | CLK | _ | |____________| _|_ | |_/\ ___| adcv0831 \ / Local |_| \/ V Gnd This relationship ofsupply bypass to signal path ofADC seen in the lab using the test circuit shown Because of ESD requirements, all pad are going to have around 5pF of capacitance. every digital input or output pin going to cause some supply current to flow through 0.1uF capacitor and ADCV0831's ground lead. , sample and hold only has access to internal ground node to which references its Analog input voltage. When change lead length of supply bypass capacitor, can modulate analog input voltage which is what graph shows below. First Code Transition ^ /_\ | 2.2_lsb _| * * | * 2.1_lsb _| * | * * 2.0_lsb _| | * * 1.9_lsb _| | * 1.8_lsb _| * * | |______________________________________|\ | | | | | | | |/ 2mm 3mm 4mm 5mm 6mm Supply bypass Lead length This type input modulation consistant. should not effect linearity of the ADC. present test system may have linearity modulating error. major code transition on test is coming close to having missing code while the lab set up does not correlate This error only possible if the Data output signal from DUT is getting back into the analog signal line. ____ Sample and Hold 10nsec after this edge _|_ \ / V ____ CHIP SELEC ___ |_______________________________________________| _ __ __ __ __ __ __ __ __ __ __ | | | | | | | | | | | | | | | | | | | | | | | V | V | V | V | V | V | V | V | V | CLOCK |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |__ ________________________________________ | | | | | | | | | ............|Bit7|Bit6|Bit5|Bit4|Bit3|Bit2|Bit1|Bit0 |... TRI STATE |____|____|____|____|____|____|____|_____| TRI STATE Data Output signal comes well after external analog voltages capture, reducting feedback from output to input should not be that hard. input sample and hold circuit need an external digital signal to tell when to capture analog signal. Care taken in design to have few of things happening possible inside die untilsample and hold process is done. still youhave a digital input signal and how much time to wait until you sample? Supply bypass ____________ 0.1uF | | _______| |_________________ _|_ |___| 1 6 |___| __________ 50_Ohms ___ VCC | SOT6 | CS | ______|_______| |_______\__________ | _|_ |___| 2 5 |___| /__________ 50_Ohms _|_ ___ GND | | DOUT | \ / |_________| |_______\__________ V Local | |___| 3 4 |___| /__________ 50_Ohms Gnd | VIN | | CLK | _ | |____________| _|_ | |_/\ ___| adcv0831 \ / Local |_| \/ V Gnd offical end point offset will probably be defined as what part measures in a common lab set up. On SOT production tester, things more challenging in that nothing can come up close to DUT. all cable are at least 2 feet long. have to generate a local ground close to DUT such that really apply an accurate Analog input voltage. capacitor form local ground to input appears to common mode out most of trouble input pin draws no current and some resistors can be added if they help. Hopefullycan geterrors small or at least consistant. best to spec end point offset numbers separately on the spec so they can be handled independently.