[Elecraft] K3 APF

[Joe Subich, W4TV]

Paul,

>> It seems that APF is really the inverse of the notch function.
>> Perhaps a quasi anti-LMS algorithm could be used to establish Auto
>> APF.

That's exactly the CW noise reduction algorithm.  I've seen Lyle write
many times that the NR builds a low order filter around any coherent
signal in the passband.  For an "auto-APF" I'm sure the issue would be
to decide *which* coherent signal to build the filter for.

73,

    ... Joe, W4TV


On 10/31/2010 10:54 PM, Paul Christensen wrote:
>> "In the RTTY world, "twin peak filters" available in many rigs often give
>> better results only because many software demodulators do not come with
>> matched filters.  "
>
> Chen,
>
> So far, nobody has discussed the possibility of an "Auto APF" feature that
> functions much like Auto Notch, but would automatically track the peaking
> frequency in the event RIT was engaged, for example.  Within limits, such a
> function would allow for hands free APF as the received pitch is changed by
> the operator.  Consider an automatic DSP notch filter that uses the LMS
> algorithm.  It seems that APF is really the inverse of the notch function.
> Perhaps a quasi anti-LMS algorithm could be used to establish Auto APF.
> Does such an algorithm now exit by name?
>
> Paul, W9AC
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>