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