RE: SJTP:Phantom sync headers
Pat,
So, you are saying that for any combination of seed and data input, that
every combination of two consecutive bits within the 64 (including the first
and last in combination with the appropriate bit of the sync bits), will
ALWAYS have at least one '00' or one '11' within 64 iterations (64x64) bits?
How do you know that?
I know that it is definitely not true for 2 iterations; and is definitely
true if the pattern is repeated in its entirety (2 ** 53 iterations) . I
can't even offer a hypothesis on how to know the length at which this
reverts from not true to true across all permutations and combinations.
jonathan
> -----Original Message-----
> From: pat_thaler@xxxxxxxxxxx [mailto:pat_thaler@xxxxxxxxxxx]
> Sent: Thursday, May 10, 2001 4:38 PM
> To: bbrown@xxxxxxxx; stds-802-3-hssg-serialpmd@xxxxxxxx
> Subject: RE: SJTP:Phantom sync headers
>
>
>
> Ben and Jonathan,
>
> As long as the pattern is being generated by setting the
> scrambler with a
> seed then letting the scrambler run with a fixed 64 bit data
> pattern into
> it, the patterns will not have any location that mimics the
> sync header. One
> would have to design a continuously changing data pattern
> synchronized with
> the seed load to get a data transition in a consistant spot
> for over 64 code
> blocks. If a repeating data pattern did that for any
> scrambler seed, it
> wouldn't be a very good scrambler.
>
> Regards,
> Pat
>
> -----Original Message-----
> From: Ben Brown [mailto:bbrown@xxxxxxxx]
> Sent: Thursday, May 10, 2001 9:59 AM
> To: serialpmd
> Subject: SJTP:Phantom sync headers
>
>
>
> All,
>
> Jonathan brought up an interesting point that I have
> elaborated upon below. Those who have begun or are
> interested in beginning to search for patterns should
> probably keep this in mind.
>
> Ben
>
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