On Jun 26, 12:41*pm, "Joel Koltner"
wrote:
"As sharp as possible" and "doesn't distort the signal too much" are somewhat
conflicting goals:

Understood, part of the point of this thread which was to get an idea
of how much group delay variance is acceptable for various types of
transmissions without greatly impacting the quality of the received
signal.

hence the trend to have somewhat "looser" analog filters (and thus low
group delay variation) and then do whatever you want digitally.

Also understood, it's all about balance. Going narrow impacts group
delay variance which distorts signal, going wide impacts dynamic
range.

Which still leaves me with the notion that you want to go as tight as
reasonably possible and no tighter. With that in mind it sounds like
what we've determined so far with regards to IF filtering is:

transmission type receiver group delay variance
-------------------------------------------------------------
CW should be less than 2 ms

this is based on Tim Shoppa's posts which were to the point.
Does anyone else have data to contribute?

-- John