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Design >> Mixed-Signal Design >> Phase Noise Adder for Cable
https://designers-guide.org/forum/YaBB.pl?num=1441748553

Message started by MarkS on Sep 8^th, 2015, 2:42pm

Title: Phase Noise Adder for Cable
Post by MarkS on Sep 8^th, 2015, 2:42pm

Hello, I am attempting to create a rough analytical model for distribution of a low-jitter clock from Board_A to Board_B across approximately 10m of cable. I have a phase noise plot for the source clock, and have done approximations for other components in the chain of Board_A, which I can add in quadrature (aka RSS) to get a composite jitter number for the output at Board_A. But how can I approximate the jitter added by the cable between Board_A and Board_B? Even if I get s-params, I need to somehow use that to come up with type of model for how much phase noise the cable would add. Any suggestions? Thanks for any thoughts you may have. I haven't seen this analyzed elsewhere (at least not that I could find, anyway).

Title: Re: Phase Noise Adder for Cable
Post by loose-electron on Sep 10^th, 2015, 10:34am

cable will give a signal degeneration which leads to a slower rise/fall characteristic.

Noise added to a defined rise fall characteristic leads a resulting spread in time of the resulting clocking signal

long cables and clocks, generally it is wise to recover the clock and use a PLL to get something clean again