K2: KDSP2 - open source questions

[Andrew Moore-3]

I'd like to have a variable bandwidth filter on my K2, controlled by an
encoder instead of a pushbutton with programmable steps.

I see the KDSP2 module uses open source code.

Would it allow me to sense a couple binary inputs (or even a variable
voltage) and write some code to vary the filter bandwidth accordingly?  Just
how flexible/programmable is it?

Thanks,
--Andrew, NV1B
..
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[KK7P]

  There has been some discussion on the reflector of late bout Tx mic
equalization.

If you have a P3, you can set the span to +/- 50 kHz or less and easily
see the results of such Tx equalization on other stations.

You'll often see two disinct patterns of SSB signals:

1) Those that look "sloped" in the spectrum.  On 20 meters, for example,
many signals look like they peak 10 or more dB on the low low side near
the carrier.  These are typically transmitters with no low cut in the Tx
equalization.

2) Those that appear nearly flat-topped in spectrum (not to be confused
with over-driving a transmitter amplifier stage).  These operators have
equalized their systems to reduce the low frequency dominance of their
audio.  The more equally filled spectrum makes pretty good use of the
peak power capabilities of the transmitter.

---

If you tune into these signals and listen to them, you will usually find
that the "flat spectrum" speech has more dominance but still has good
fidelity.

You can learn a lot with the P3 :-)

73,

Lyle KK7P


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[KK7P]

  The DSPx module hardware does not include an ADC to measure  control
voltage, but it does have some unused digital I/O pins that could read
buttons, or perhaps an encoder, if you wrote the code to do it.

There is plenty of unused program memory and lots of available DSP
horsepower for such things.

73,

Lyle KK7P

> I see the KDSP2 module uses open source code.
>
> Would it allow me to sense a couple binary inputs (or even a variable
> voltage) and write some code to vary the filter bandwidth accordingly?

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[alorona]

Lyle, I have been noticing the same things. There are a lot of signals with that
characteristic low frequency rise. And as low frequencies rise, intelligibility
and punch fall.

But not only phone signals... one can see -- at suitably narrow spans-- which CW
signals take up more spectrum than others. Here, the P3's peak hold feature
helps to exaggerate the differences between signals. There are some CW signals
out there that are real spectrum hogs, thanks probably to the too-sharp
transitions on their keying waveforms. This defect is easily seen with the P3.

Al  W6LX




________________________________
 
If you tune into these signals and listen to them, you will usually find
that the "flat spectrum" speech has more dominance but still has good
fidelity.

73,

Lyle KK7P
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[Guy, K2AV]

They're called key clicks...nice to be able to SEE them now :>)

73, Guy.

On Tue, Sep 7, 2010 at 9:11 PM, Al Lorona <[hidden email]> wrote:

> Lyle, I have been noticing the same things. There are a lot of signals with that
> characteristic low frequency rise. And as low frequencies rise, intelligibility
> and punch fall.
>
> But not only phone signals... one can see -- at suitably narrow spans-- which CW
> signals take up more spectrum than others. Here, the P3's peak hold feature
> helps to exaggerate the differences between signals. There are some CW signals
> out there that are real spectrum hogs, thanks probably to the too-sharp
> transitions on their keying waveforms. This defect is easily seen with the P3.
>
> Al  W6LX
>
>
>
>
> ________________________________
>
> If you tune into these signals and listen to them, you will usually find
> that the "flat spectrum" speech has more dominance but still has good
> fidelity.
>
> 73,
>
> Lyle KK7P
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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