[Lf] [Fwd: LF: Demodulator program for the W & G Pegelmesse]

[Frank Gentges KØBRA]

We need to try this out.  The last IF of the RX320 is 12 kHz so this 
software might have something to add.  I assume it needs a full duplex 
sound system.  But for now I must head out the door to take care of more 
mundane business for a week.

Frank   K0BRA


At 10:19 AM 3/13/02 -0500, Andre Kesteloot wrote:

>Alberto di Bene wrote:
>
> > Many LF enthusiasts have a Selective Level Meter, generally
> > made by Wandel & Golterman. Some of these units have a
> > demodulated output, others don't, instead providing a last
> > IF output at 10 kHz on the rear panel.
> >
> > For this last kind of equipment I have written a sort of last IF
> > stage in software, which accepts as input a frequency between
> > 40 and 20000 Hz, and extracts the AM, USB or LSB modulation
> > it may have, playing it through the PC sound card.
> >
> > The program sports also a graphical Phase Meter, which works
> > only when AM is selected, and measures the incoming carrier
> > phase referred to the program 'BFO' phase. It can be used for
> > a very superfine tuning. A frequency difference of 1 Hz between
> > the incoming signal and the BFO produces a whole revolution
> > every second, so frequency differences of 10 mHz are easily
> > appreciated.
> >
> > The program does not touch the audio mixer, so it's up to the user
> > to set it correctly. Basically you have to set the Recording panel
> > so that only Line In is selected, and the Playback panel so that
> > only Wave is selected. Make sure that Line In is *deselected*
> > for Playback.
> > Of course you will have to connect the 10 kHz output of your
> > Selective Level Meter to the Line In of the sound card.
> >
> > The program has a very serious problem, as the played audio lags
> > the input by almost a second, so tuning is quite difficult.
> > This is due to the processing of the signal, and to the MME system
> > of Windows. There are ways to improve this, and maybe I will
> > pursue this, depending on my spare time and the acceptance
> > of the program.
> >
> > Bear in mind that this is just a first cut, more an alpha version than
> > a beta, so do not have excessive expectations.... I wrote it more
> > as an exercise, using some routines I had already written for
> > the version 0.93 of Jason (to be released).
> > Of course any criticism, suggestions, bug reports are welcome.
> >
> > The program can be downloaded from :
> > http://www.weaksignals.com/bin/radiopak_090.exe
> >
> > 73  Alberto  I2PHD
>
>
>
>
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Frank Gentges KØBRA
<fgentges at mindspring.com>
LF web site at <http://www.amrad.org/projects/lf>