[Elecraft] RE: Difference between "real" filters (FL1 thru FL4) and DSPfilters (SF1 thru SF4)

[Steven Pituch]

Hi John,
The DSP is audio.  Its got a sharper cutoff but can be affected by the AGC
which is also audio.  The crystals filters FL1 -FL4 are IF and closer to the
front end and cut interference before the AGC.

Yes, in non critical situations, the DSP filters are sharper, but if a loud
adjacent signal gets through the IF because a narrow IF filter is not being
used it will activate the AGC and desense the signal you are listening to.

The best thing to do is narrow it down first with the IF filters, and then
use the DSP narrow bandwidths if the IF filtering is not enough.

I have some samples of the bandwidths here.
http://users.ev1.net/~spituch/Steve's%20Page/Radio/RTTY/RTTY.html
By the way, using MixW to align the filters was very easy.

Regards,
Steve, W2mY/5

-----Original Message-----
On Behalf Of John Wiener
I have been playing with the KDSP2 on my K2 and was wondering if the DSP
filters are significantly different in their effects than the effects of
filters FL1 thru FL4.
To me, they seem a bit redundant, in terms of audio effect on listening.

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