[802.3_100GCU] Suggested remedy for comments #70 and #71

[Liav Ben Artsi <liav@xxxxxxxxxxx>]

Hello all,

We would like to address comments #70 and #71 against draft 2.1

The comments basically question the required amount of COM for Rx interference tolerance testing and channel qualification.

Estimating the impact of implementation errors on the required COM we have come up with the following COM budgeting:

1.      CDR tracking error jitter. Was tested in two ways:

o   what happens if we have a sampling location error of 1/32UI – changed the COM code to introduce this sampling error.

o   if the CDR tracking introduces additional dj which was account for by doubling the A_DD value.

2.      DFE tap granularity error of 2% of the available signal

These two impacted the COM result with a combined impact of up to 2.2dB.

3.      Other implementation impairments may include: Rx PSRR, Rx CMRR impact, Mode conversion, Receiver non-linearity, slicer sensitivity, termination mismatch and PKG Xtalk.

4.      Taking into account points 1-3 above it is recommended that the Rx interference tolerance test stress be tuned to 3dB.

5.      For the test to guarantee that compliant receivers will work with compliant channels, we can put in some margin by setting the "compliant channel" bar higher than the Rx interference tolerance COM target. A suggested margin of 1 dB results with a channel COM target of 4dB.

 

Best regards,

Adee and Liav