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Re: [802.3ae] RE: [802.3ae_Serial] 802.3ae PRBSs are upside down

We're making good progress :-)

"THALER,PAT (A-Roseville,ex1)" wrote:

> Thanks for pointing this out. I was looking at the Agilent 81250 BERT which
> has a box where you can select normal or inverted. Looking at the appendix,
> it turns out that "normal" chooses a PRBS that is inverted from the output
> of the generator. "Inverted" chooses the direct output of the inverter. That
> is, normal chooses the PRBS with a run of n 0s for an order n polynomial and
> inverted chooses the PRBS with a run of n 1s.
> There is a note to the effect that if you are having trouble getting two
> testers to work then try switching the inversion.
> Well, you can select between two choices and they are inverses of each
> other:
> normal = inverted
> inverted = not inverted

That brings us full circle to Piers' point. Since normal = inverted, is it
beneficial for us to mandate the use of the inverter on the output of the
PRBS31 we have specified, such that:
1) Test equipment users will assume it is a normal PRBS31?
2) We don't have to go through this discussion everytime we receive
a complaint that the DUT won't sync to the tester?

P.S. normal = inverted = O.150

Tim Warland  P. Eng.
Applications Engineer
Quake Technologies   (613)270-8113 ext 2311

Shake things up.