8b/10b

Hi,
What is the meaning of DC balance in 8b/10b?
Any good tutorial on 8b/10b encoding ?
I search through google but cant give me a good one.
Thanks in advace.

 

DC balance means that, over some (agreed upon) maximum number of data bits,
there are equal number of 1's (positive voltage) and 0's (negative voltage).
This is required because the signal that has been encoded needs to be passed
either through a capacitor and/or a transformer (both of which will not pass
a signal whose average level is anything but zero volts).

Also, the coded bytes (every 8 bits are encoded into a 10 bit word) ensure
that there are enough transitions between 0's to 1's (and 1's to 0's) so
that a clock can be regenerated at the receiving end.

There should be a ton of stuff on the web. You're not searching hard enough
if you haven't found what you need.

Bob

 

tatto0posted:

<< What is the meaning of DC balance in 8b/10b?
Any good tutorial on 8b/10b encoding ?
I search through google but cant give me a good one.
Google search for "8B10B code" and for more than you want, search for
"transmission line-code."

Don

 

Yes, this is what I am looking for. "Troublesome" keywords I have been used.