[Elecraft] Auto Notch on CW?

[Alan Bloom]

On Fri, 2008-02-22 at 09:30, Björn Mohr wrote:
> This just got me thinking... Wouldn't it be possible write instructions to
> the auto notch to stay away from a signal right in the centre of the pass
> band. It just have to read the pitch setting and don't notch signals there.
> At least that would help to remove some of the sporadic tuners that never
> bothers to listen. All the operator has to do is to make sure to zero beat
> the other station. I am no programmer, but has this option been considered
> before?

I believe the LMS (least-mean square) algorithm used for autonotch
automatically notches all CW signals.  It would probably be quite
difficult to modify it to treat some frequencies differently than
others.

> In theory it makes sense to me, but I have no clue what would be involved to
> make it work.

Probably the way to do it is to (1) process the input signal using the
standard LMS algorithm, (2) also process the input signal with a narrow
band-pass filter tuned to the center of the passband, and then (3)
combine the output of the two processes.

It seems like that should work and wouldn't be too hard to implement.

Al N1AL