Hi, I'm trying to modulate data using FSK and transmit it from one PC to another via the sound cards. This involves two applications which I will build, one which modulates on PC 1 and the other which demodulates on PC 2. At the moment I've created an application on PC 1 which modulates then demodulates the signal, using the MT Modulate FSK and MT Demodulate FSK VIs. I made this application to figure out how to make the modulation VIs work correctly together, the next step is to split this application into two applications and add sound card outputs and inputs to them. The problem I'm having when adding the sound output to the modulating application is that the output of the MT Modulate FSK VI is a complex waveform, whereas the input of the Sound Output Write VI is just 'data'. At the moment I've unbundled the complex waveform and used just the Y component as the input for Sound Output Write. In the first instance this appears to work - the application runs and you can hear a digital sounding signal playing through the speakers. Unfortunately, upon analysis of the output signal, it can be seen that whatever is being output is not a properly modulated FSK signal, but an apparently nonsense signal which will not demodulate successfully. This appears to be because there is some data from the complex signal which is not being used, which is necessary for propery regeneration of the signal. Has anybody tried outputting an FSK modulated signal (or any complex signal) through a sound card before, and if so, how did you pass the data to the sound card successfully? If nobody has done this before, does anybody have any idea how I might successfully pass the entire complex waveform to the sound card? Many thanks, Andy

LabVIEW

How to output a complex waveform with a sound card

Hi,

hope you're still around...
I'm working on exactly the same problem. Have you managed to make the transmission via sound card working? I would also be interrested to know how you tweaked the guard bits.

Cheers,

Markus

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LabVIEW

How to output a complex waveform with a sound card

Re: How to output a complex waveform with a sound card