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LF: RE: Problem with generator to VLF transmitter

To: "[email protected]" <[email protected]>
Subject: LF: RE: Problem with generator to VLF transmitter
From: Rik Strobbe <[email protected]>
Date: Sun, 2 Dec 2012 21:53:12 +0000
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Thread-topic: Problem with generator to VLF transmitter

Hello Marcin,

 

generating 2 counterphase sine signals can be easily done with a soundcard.

But as you are speaking of duty cycles I assume that you want a square wave signal and there you are limited by the sample rate of the soundcard. These days 192kHz soundcards are easily available, was means a sample each 5.20833.. microseconds.

For 8970Hz the closest frequency is 8727.2727.. Hz (192000/22).

If you want to use a soundcard your best option may be to generate sine signals and use a hardware discriminator to convert them to a square wave. 

If I am not mistaken you could use DL4YHF's Spectrum Lab software as it has a test generator option.

 

73, Rik  ON7YD - OR7T

 

 

 


Van: [email protected] [[email protected]] namens Marcin [[email protected]]
Verzonden: zondag 2 december 2012 21:42
To: [email protected]
Onderwerp: LF: Problem with generator to VLF transmitter

Hi All!
We’re building an 8,970kHz VLF transmitter at SP2KDS club.
We almost have everything in place:
 
What we still need is a generator to feed the transmitter. Required parameters are the following:
  • 8,970kHz frequency
  • regulating range +-0.05Hz
  • adjusting duty cycle of 5 to 45%, at 5% for two signals at the same time
  • two signals shifted by 180 degrees
A friend of mine has promised to build it but it’s been over a year now and nothing has happened.
Is there a software which would use a soundcard with the aforementioned parameters?
 
73! Marcin SQ2BXI
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