Message-ID: <000701c1cabb$735db260$1c076c0a@arenanet.fi>
From: "Matti Niemela" <mattis.niemela@kolumbus.fi>
To: rsgb_lf_group@blacksheep.org
References: <3C8F5B55.B8F16F2F@usa.net>
Subject: LF: Re: Demodulator program for the W & G Pegelmesse
Date: Wed, 13 Mar 2002 20:18:18 +0200
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Thank You Alberto for nice PHD Radio-program. It works great with my R&S
SPM19 level meter. The sound quality is surprising good. The one second
delay is not a problem.

73 de Matti/OH2ZT
----- Original Message -----
From: "Alberto di Bene" <dibene@usa.net>
To: "LF Mailing List" <rsgb_lf_group@blacksheep.org>
Sent: Wednesday, March 13, 2002 3:59 PM
Subject: LF: Demodulator program for the W & G Pegelmesse


> 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
>
>
>