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Design >> High-Speed I/O Design >> What is difference between pre-emphasis and PR response?
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Message started by neoflash on Sep 13^th, 2011, 3:04pm

Title: What is difference between pre-emphasis and PR response?
Post by neoflash on Sep 13^th, 2011, 3:04pm

They all appears to be a Tx side FIR filter. What is their difference? Can I say that Tx pre-emphasis is a kind of PR response pre-coder?

Title: Re: What is difference between pre-emphasis and PR response?
Post by loose-electron on Sep 14^th, 2011, 12:16pm

Pre-emphasis is spectral shaping at the tx to compensate for the spectral shape (LPF sort of) of the comm channel.

In SerDes, that can be seen in the time domain, by amplitude boosting the transient edges of the signal.

PR = partial response - usually means bandwidth limiting the receiver input to reduce noise content. However, that also means reducing the higher harmonic content of a signal, thus the term "partial" response.