[SI-LIST] Re: Bit pattern for high speed serial link simulation

Steve:

Thanks for the suggestion. This is through encoder. I'm running a PRBS15
pattern simulation right now (already a week) and I do noticed closure of
eye mask due to the pattern. May try an even longer pattern but the
simulation in hspice is just too slow. Will probably look into Allegro PCB
SI channel analysis tool.

Regards

Perry

 
======================================= 

Perry Qu 

Design & Qualification, Alcatel Canada 

600 March Road, Ottawa ON, K2K 2E6 

DID: 613-7846720  Fax: 613-5993642 

Email: perry.qu@xxxxxxxxxxx 

======================================= 


-----Original Message-----
From: steve weir [mailto:weirsi@xxxxxxxxxx] 
Sent: Monday, November 28, 2005 4:26 PM
To: Perry.Qu@xxxxxxxxxxx; si-list
Subject: Re: [SI-LIST] Bit pattern for high speed serial link simulation

Perry, if you are bypassing the encoder/decoder, then PRBS7 generates
sufficient run-length.  If you are driving the encoder, you want a run
length > 15, so PRBS21 or PRBS31 would be a better choice.

Steve.
At 03:21 PM 11/28/2005 -0500, Perry Qu wrote:
>Hi,
>
>What will be a realistic bit pattern to use for simulation of a serial 
>link
>(3Gbps) with 8B/10B encoding ? Right now I used PRBS7 pattern but I'm 
>not sure whether it captured the worst case pattern compared to 
>reality, where the live data traffic is a lot more random. 8B/10B has a 
>run length of 5 but if it's fed with say a PRBS31 bit stream, will I 
>get more spectrum peaks than just a pure PRBS7 pattern without encoding 
>which repeat itself every
>127 bits ?
>
>Thanks
>
>Perry
>
>=======================================
>
>Perry Qu
>
>Design & Qualification, Alcatel Canada
>
>600 March Road, Ottawa ON, K2K 2E6
>
>DID: 613-7846720  Fax: 613-5993642
>
>Email: perry.qu@xxxxxxxxxxx
>
>=======================================
>
>
>
>
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