2004/12/15V1.0 10GMMF1 TP2 Waveform Capture Pavel Zivny with input from Greg LeCheminant

2004/12/15V1.0 10GMMF2 TOC  Proposal for the “TP2 – CR and Trigger method”  “Issues for jitter/noise analysis”  TP2 uncorrelated jitter/noise measurements

2004/12/15V1.0 10GMMF3 TP2 - CR and Trigger method Proposal:  Record the single valued data pattern waveform (rather than the eye diagram) using a synchronizing timing reference obtained with a clock recovery unit having a characteristic as described in “802.3ae Transmitter optical waveform”*. If a sampling oscilloscope is used, the pattern waveform is acquired by means of triggering on divided recovered clock (the recovered clock is divided by the pattern length to produce a trigger edge occurring once per pattern repetition).  Only bits through of pattern are analyzed. The bits are recognized by their position relative to the longest transition-less sequence in the pattern. In particular the bits are located UIs after the sequence. *See next page

2004/12/15V1.0 10GMMF4 TP2 - CR and Trigger method Supplementary info: CRU per 802.3ae From 802.3ae Transmitter optical waveform “A clock recovery unit (CRU) should be used to trigger the scope for mask measurements as shown in Figure It should have a high-frequency corner bandwidth of less than or equal to 4 MHz and a slope of -20 dB/decade."

2004/12/15V1.0 10GMMF5 Issues for jitter/noise analysis  Measured uncorrelated jitter and noise are assumed Gaussian or other high probability jitter. Low probability, high PkPk value jitter/noise escapes detection through RMS test. Mask test captures this, if there’d be no mask test this would need addressing in another way.  P j, P n are both bundled into R(andom) component That’s a pessimism. Comment from Xmitter designers desireable – is P ever a problem?  Always measure with the ORR on. Is there a consensus on this?

2004/12/15V1.0 10GMMF6 Background Information Three methods of Jitter/Noise Analysis 1. Analyze an LF square-wave +Simplest Measurement equipment setup − Signal far from natural − Dedicated pattern not useful for other measurements 2. Analyze Dedicated bit(s) within a Multi-use 348-bit Stress Pattern +Useful, near-natural pattern +R j and R n measurements simple & easily verifiable − Needs Trigger on Pattern (with e.g. a bit countdown trigger) − Needs a bit search (not implemented today) 3. Perform complete Jitter/Noise analysis (R j and R n, DD j and DD n ) on the whole Pattern (e.g. the Multi-use 348-bit Stress Pattern) +Useful, near-natural pattern +Complete Jitter/Noise measured (rather than just one, possibly special, bit) − Needs Trigger on Pattern (with e.g. a bit countdown trigger) − Needs complete jitter/noise analysis package (single source, marginal availability today) Current choice