[RTTY] Filters

[Jim Reisert AD1C]

At 10:21 AM 3/24/2004, Bill Turner wrote:

>When I'm using a 250 Hz filter, quite often when two stations are within
>10-20 Hz of each other and nearly the same strength, I can tune off to
>the side and get clear copy, something that probably would not happen
>with a wider filter.  Just something to keep in mind.

This doesn't have anything to do with the filter bandwidth, but rather the 
shape.  If the shape is very "square" then you will get good rejection just 
outside the passband.  If it slopes more gradually, the rejection will be 
reduced.  DSP filters like in the IC-756 are very good at these sorts of 
things.

73 - Jim AD1C


-- 
Jim Reisert AD1C, 7 Charlemont Court, North Chelmsford, MA 01863
USA +978-251-9933, <jjreisert at alum.mit.edu>, http://www.ad1c.com
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