RFSA FSK Demodulation: Output bits stream received without emission

[Guetteur]

Hi,

Just to mention that i tried both solutions. I mean, putting the reference level at -30 dbm, and amplifying the signal, but without success, the result is the same; the bits received are not the one emmittend by the device.

Please see attached the signal after the amplification.

Best regards !

[Yardov]

Hello Guetteur,

As mentioned before, your reference level should be set at -30 dBm. This should help more bringing that noise down. Post a picture if you want so I can see the change.

A DSP technique is not that easy if you don't know what you are looking for. The match filter is suppose to minimize the noise. Any other DSP technique will require a good understanding of what you are looking for and that is somehow dependent of your application so there is no "general" answer or "general" VI.

Regards,

[Guetteur · Accepted solution]

Hi again,

First of all, sorry for this late response.

As Seb_MDI was asking the same question as mine here, i would like to add more information on how i resolve the problem in order to help him or others.

Below the parameters i've changed the problem to be solved:

- Span.

- Reference Level.

- Resolution Bandwith.

All those parameters could be set by using the "ni5600 Configure for Spectrum.Vi"

Also i've measured exactly my device fsk parameters. The FSK demodulation example vi depends a lot on the Sample Rate variation (even a very tiny variation).

An other very important parameter is the "time duration (sec)" input of the "ni 5660 Configure for IQ.vi". The signal should be received exactly during this period, in order to be analyzed.

Best regards