Hello, has anyone already used a Spartan IIe DLL (PLL) to extract the clock out of a 100MBit/s 8B10B encoded data stream ?
Will that work with a Spartan III DCM?
Thank you, Thomas
- posted
20 years ago
Clock Recovery from 8B10B encoded Data Stream
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- posted
20 years ago
Thomas,
The DLL can not be used to extract clock, as the output is just the input, delayed.
In Spartan 3 there are "hidden" modes in the DCM that allow us to experiment with things like CDR, so you will have to wait until we have fully characterized the capabilities, and decided if they work well enough to market and support.
The exciting thing about the DCM and all of its capabilities is that we can see our way to an all digital DSP implementation of a PLL -- without any of the negatives of a PLL. Including jitter attenuation (something not done in today's DCM).
If you are interested in using the S3 unsupported modes, you would have to work through your factory or disti FAE with us.
Another option is to oversample the 100Mbs with the MGTs in Virtex II Pro.
And finally, there are other designs using logic alone to recover the datastream of such a low bit rate stream in any of the Virtex family FPGAs (Xapp250, Xapp224).
Aust> Hello,