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RE: [802.3ae] WIS test Pattern PRBS Generator Polynomial




Ouch ---  I missed that comment.  Thanks for pointing it out.
My issue was that there are MANY 2**23-1 polynomials.  Which one
specifically is preferred or required was not specified, and there
was no comment indicating that the choice was implementation
dependent or to be determined in the future.  

Bruce

> -----Original Message-----
> From: Tom Alexander [mailto:Tom_Alexander@xxxxxxxxxxxxxx]
> Sent: Monday, February 04, 2002 9:36 AM
> To: Nepple, Bruce; stds-802-3-hssg@xxxxxxxxxxxxxxxxxx
> Subject: RE: [802.3ae] WIS test Pattern PRBS Generator Polynomial
> 
> 
> Bruce,
> 
> The PRBS for the mixed-frequency test pattern indeed uses a 
> 2**23 -1 polynomial. This is explicitly described in the WIS 
> clause (see lines 39-41 and 47-48 of page 397, lines 9-13 of 
> page 398, and Figure 50-13 (payload field) on page 398). All 
> these refer to Draft 4.0.
> 
> Note that in the next draft of the WIS spec, there is a new 
> (optional) additional test pattern introduced, as per the 
> resolution of Comment #72 against Draft 4.0; this pattern 
> uses a 2**31 -1 polynomial.
> 
> Thanks,
> 
> - Tom Alexander
> WIS Scribe
> 
> 
> -----Original Message-----
> From: Nepple, Bruce [mailto:bnepple@xxxxxxxxxxxxxxxxxxx]
> Sent: Friday, February 01, 2002 9:36 PM
> To: stds-802-3-hssg@xxxxxxxxxxxxxxxxxx
> Subject: [802.3ae] WIS test Pattern PRBS Generator Polynomial
> 
> 
> I could find no definition of the WIS test Pattern PRBS 
> generator polynomial in Clause 50 (or any other clause, for 
> that matter).  I did find a reference to O.172 and in O.172 I 
> found a reference to O.150, and in O.150 I found a definition 
> for a 2**23 -1 length PRBS. (Section 5.6).  Is that the 
> required generator for WIS?  Is there a reason that it is not 
> specified?  Or, did I just manage to overlook it in the 
> specification? (wouldn't be the first time).
> 
> O.150 Section 5.6 specifies a 23 stage shift register with 
> taps from stage 23 and stage 18 added (mod-2) and applied to 
> the first stage. (I'd call it a x**23 + x**18 + 1 generator 
> with input data = 0, but I'm not a math dude)
> 
> Bruce
>