Re: [802.3_100GCU] Item 2: preprocessing s-parameters. 802.3bj Consensus Building Group - Channel Specifications

[Vivek Telang <vtelang@xxxxxxxxxxxx>]

Rich,

 

Agree with 1, 2 and 3.

 

For 4, why not specify the Tx and Rx terminations as s-parameters, and let the concatenation take care of all the reflections.

Also, we should add:

5. Tx/Rx package s-parameters.

 

Then the end-to-end channel model would simply look like:

S_txterm*s_txpkg*chan*srxpkg*s_rxterm (* implies s-parameter concatenation)

 

Vivek

 

From: Mellitz, Richard [mailto:richard.mellitz@xxxxxxxxx]
Sent: Friday, June 08, 2012 9:19 AM
To: STDS-802-3-100GCU@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_100GCU] Item 2: preprocessing s-parameters. 802.3bj Consensus Building Group - Channel Specifications

 

Perhaps a convenient way to look at TX/RX filtering is convolution of the following.

 

1.       Tx Voltage Amplitude scaling (for NEXT, FEXT, and THRU not coding which will be done in a later algorithm )

2.       Tx edge filter (moore_01_0311)

3.       Rx bandwidth filter (moore_01_0311)

4.       Tx/Rx block return loss filters (gamma,moore_01_0311)

 

The first three are a straight convolution and with is multiplication in the frequency domain.

 

The lasts is a chain matrix convolution of RL under worst +1 or -1 reflection coefficient  phase conditions and in the frequency domain may look like this

 

sdd21=sdd21.*(1.-gamma_rx)./(1.- sdd11.*gamma_tx + sdd22.*gamma_rx +sdd21.^2.*gamma_tx.*gamma_rx -sdd11.*sdd22.*gamma_tx.*gamma_rx);

 

…Rich