======================EYE_PATTERN============================= ________________ \/ \/ Eye Pattern SONET OC-3 ____/\____/\____ Eye_Pattern digital data transmissions SONET, SDH fiber channel used to evaluate determine the health of the DUT and conduct compliance testing to industry standards ________________ \/ \/ Eye Pattern ____/\____/\____ ___________ / ____/ 1 _ __ \ / \__________/ 2 ____ \ \_________ 3 __________ / \ _/ \__ 4 ____ ____ \ / \____/ 5 ____ / __________/ 6 ____ / \ ____/ \____ 7 ___________ \ \____ 8 eye diagram a cumulative graphical portrait edge placement due to noise of jitter can locate tIme reference edge examine the jitter on subsequent edges. ---------------------------------------------------------------------------- Jitter Degrees intervals (Uls) intervals (Uls) power Peak-to-peak jitterpsec peak-to-peak peak-to-peak. rms units.(dBui (6.43 nsec=1 cycle) normalized normalize normalize 100 5.6 0.015552 0.0022217 „53.07 200 1.12 0.003110 0.0004443 „67.05 Notes: RMS UI calculation uses 1/7th of peak-to-peak jitter approxim. dBui means dedbels relative to one unit interval. Low-freq High-frequency Frequency Cost jitter jitter generation 1 lowest 1 best 1 best. techniques 3 highest 3 worst 3 worst Comments Type Direct clock/TCXO 1 2 1 or 2 Very good jitter A Direct VCXO 2 1 1 or 2 Very good jitter B Direct oven 3 1 1 Exceflent jItter C Tuned Multipily 2 1 1 or 2 periodic jitter D DiscretePLL 2 2 2or3 Goodjitter E MonolightPLL 1 3 2or3 close in poor F TCXO temperature-compensated crystal oscillator. VCXO voltage-controlled crystal oscillator. Close-in jitter is typically jitter with a frequency