[SI-LIST] Re: purpose of 8b/10b encoding

Jeffrey,

Thanks for the feedback.

Looking at the spectrum of an un-encoded/raw data stream versus
an 8b/10b-encoded data stream, I can see how the power
spectral density will be increased at a frequency
equal to the data rate/2, which would provide more
information for a PLL to synch onto.

If this is the case, is there a way of analyzing exactly how
much better a PLL can synch when using 8b/10b vs when
not using 8b/10b?  If there is, can the analysis be
generalized to allowing me to determine how often
transitions need to be in order for a PLL to lock?

Thanks,
Pat


> 
> # What's the purpose of 8b/10b encoding?
> 
> Generally as I understand, it is to be able to recover the clock by
> ensuring some number of transitions per period (8 per 10?). 
> Clocks change
> period frequently when working at high speeds, due to 
> temperature, etc... not
> to meantion the fact that otherwise the sending clock would 
> inevitably be
> out of phase, plus period, of your receiver's clock.
> 
> 
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu
  

Other related posts: