Brian and all,
The number of poles is not the primary deciding factor. It is the type
of filter (Cohn, Chebychev, Butterworth, Gaussian to 6 dB, Gaussian to
12 dB, etc.) that will influence the group delay. See the discussion on
filters in Experimental Methods for RF Design for further information.
In general, those filters with a 'rounded nose' will have the best group
delay characteristics - but that is only a generalization, the details
will tell "the rest of the story".
73,
Don W3FPR
Brian Lloyd wrote:
A number of messages have gone back and forth here about roofing
filters. We did mention group delay but I wonder if Elecraft can provide
group delay characteristics for the various filters offered for the K3.
Seems to me that, in general, fewer poles tend to provide better group
delay in a filter at the expense of the skirts. OTOH, if the skirts in
the roofing filter are sufficient to attenuate a strong, undesired
signal so that it cannot cause desense, then it strikes me that the
5-pole filters might actually provide superior performance for digital
communications.
73 de Brian, WB6RQN
Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com
_______________________________________________
Elecraft mailing list
Post to: [email protected]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
_______________________________________________
Elecraft mailing list
Post to: [email protected]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
