Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

Using PLL to synchronize Data stream on Cyclone III

Hi everyone, I have a 125MHz asynchronus NRZI bit-stream as an input into my FPGA. I want to sample this bit-stream and make sure, that I sample each bit once and correct. Can I use the NRZI bit ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

No. As long as can't derive a continuous square wave from the input signal, a regular FPGA PLL won't work. The PLL dynamic phase shift feature can be utilized to make a software CDR with limited frequency range, well sufficient for a data stream with crystal timed frequency.