Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

# Re: [10GMMF] TP3 calculation of OSNR for compliance test

 Lew - your first paragraph in the response implies that we want the same SNR in the test signal as in an actual signal in the application. That's a bit different than wanting to produce the same power penalty that we expect in application, which is what I think we are trying to do. The differences are related to the signal dependent (vs. independent) noise levels and optimum (vs. centered) thresholding you refer to in your submission.   The simple formula accounts for extinction ratio by its definition of Q = 1/2 of pk-pk signal / rms noise, or OMA/(2x rms noise). It requires the assumption that the noise is independent of average power. I believe your curves will approach the simple equation if you let ER go even lower.   Tom   ----- Original Message ----- From: Lew Aronson Sent: Wednesday, October 27, 2004 10:08 PM Subject: Re: [10GMMF] TP3 calculation of OSNR for compliance test What we are calculating is the S/N of a signal with relative noise, i.e. different amounts on each level, with a PP of 0.9dB.  The TP3 compliance signal will then simulate this relative noise with equal noise on each level yielding the same S/N.    Also, doesn't the simple formula still need to take into account the extinction ratio?    In any case, you are probably right that the approximation of equal power is fine.    Lew    -----Original Message-----From: Tom Lindsay [mailto:tlindsay@IEEE.ORG]Sent: Wednesday, October 27, 2004 3:22 PMTo: STDS-802-3-10GMMF@listserv.ieee.orgSubject: Re: [10GMMF] TP3 calculation of OSNR for compliance test Lew -   Your development assumes that the rms value due to RIN is proportional to the optical signal power. In the case of TP3 testing, we plan on adding a white noise generator before the E/O, such that its rms noise is ~ the same at both levels.   In this case, the math can get much simpler and should revert to the simple textbook formula PP(dB)=-5*log[1-(Q/Qn)^2], and Qn =Q/sqrt(1-10^(PP(dB)/-5)).   For 0.9 dB, Qn=12.1. (Compare to your equation (8)).   Comments? Tom   ----- Original Message ----- From: Lew Aronson Sent: Tuesday, October 26, 2004 8:45 AM Subject: [10GMMF] TP3 calculation of OSNR for compliance test Sorry for the late e-mail, my first attempt got bounced as too large a file size.Please find attached a calculation I have done for the optical S/N we need to have on the TP3 compliance signal.  It also has some calculations of the resulting EDC S/N for different receive powers and receiver front end sensitivities.Lew-----Original Message-----From: Michael Lawton [mailto:mike_lawton@AGILENT.COM]Sent: Tuesday, October 26, 2004 2:22 AMTo: STDS-802-3-10GMMF@listserv.ieee.orgSubject: [10GMMF] TP3 meeting Agenda + dial in Oct 26Dear TP3'ers,Here is the agenda for today's meeting:-Tuesday October 26th at 9am SJ, 5pm UK, 6pm GermanyDial in (650) 599-0374, Meeting ID:     136169        1. List Attendees        2. Review meeting notes from last week          3. Agenda additions/changes?        4. Static Channel Methodology                - Noise loading - review calculations from Lew                - Channel types and exact characteristics                        o review comments from Tom reference rise and fall time          5. Jitter                - Petre kindly agreed to evaluate jitter testing requirements and the need for a high frequency                  sinusoidal interferer          6. Link Budget                - I think we have agreed that the testing is designed to emulate the budget                - Do we need to do more work on the budget?                - Is our thinking on metrics changing? (PIE-L, PIE-D, fixed length equalisers)                - 300m question          7. OMA Measurement methodology                - Piers is exploring a histogram vs a slow pattern approach.I'm not expecting we work through all the items ... however I want to keep them on the agenda so we understand our work list and where it makes sense we can shift around the order.Talk to you all later.Best RegardsMIke