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

Re: [802.3_ISAAC] Questions on "GMSLE FDD PHY SIMULATION RESULTS AND PHY"

hello Conrad,

thanks for your question.  The blue curve is a 13.5m cable which I would consider 'moderate' rather than 'long' 

The black line is the proposed coax cable harness only.  MDI and POC not included.  

As for your second question, my implementation has a hybrid with good cancellation at low frequency. 
 but I have assessed adding another HPF at the receiver after the hybrid similar to Hossein's contribution with poorer cancellation at low frequency and it does not substantially change the performance results.  

regards,
Jay Cordaro
Affiliation: Analog Devices



From: Conrad Zerna <conrad@xxxxxxxxxxxxxx>
Sent: Monday, March 10, 2025 3:11 PM
To: STDS-802-3-ISAAC@xxxxxxxxxxxxxxxxx <STDS-802-3-ISAAC@xxxxxxxxxxxxxxxxx>
Subject: [802.3_ISAAC] Questions on "GMSLE FDD PHY SIMULATION RESULTS AND PHY"
 
[External]

Hi Jay,

Thanks for the presentation. I have a question on it.
You said, your "long channel" on slide 12 is close to the coax limit proposed by me. I see the black line, which says "spec" and which is close to the 21.68dB IL @3GHz.
However, the blue curve is labelled as the "channel with PoC", which is only about 16dB @3GHz. The coax limit line was proposed for Coax cable harness only, not including the PoC (which is adding IL to the channel 0.7-1.2dB @ 3GHz per MDI/side).
Connecting these data points, I would say your "long channel" is still about 7-8dB from the "worst case IL".

I also noticed, the RL is very very low with -30dB up to 400MHz. Interesting to see, that the long channel is actually showing worse RL in this middle frequency range than the short channel.
Could you comment, how much your BCI margin curve would shift when you RL is moving closer to the drawn limit?
(I also wanted to mention, that you have drawn the MDI RL limit, not the cable harness RL limit. Even the optimistic cable harness RL limit proposed by Rich and Rohit is more relaxed for 250MHz and higher.)

Thanks,
    Conrad



________________________________________________________________________
To unsubscribe from the STDS-802-3-ISAAC list, click the following link: https://urldefense.com/v3/__https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-ISAAC&A=1__;!!A3Ni8CS0y2Y!5QAkw6lrJlzcl0H-pdquevA9iC9yNinjpR0_nmSU7Rl_zOCO7e4DwH3SZrDwwK8i07G5RYy4MM8JB7JHRhC-$

To unsubscribe from the STDS-802-3-ISAAC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-ISAAC&A=1