I am trying to create a random signal in GNU Radio (using DVB-S2 specs for the physical layer) and transmit this signal using a USRP X310. This is shown below:

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Problem: I would like to be able to control the Es/No of this signal, as well as the symbol rate, but I don't know how. I'm brand new to DSP, so any help is appreciated!

Edit (2/9/2022): Removed throttle block, since it is unnecessary. To clarify, I would like to run GNU Radio on a USRP, then pipe the signal directly into another USRP to receive the signal. I would like to be able to control the Es/No in GNU Radio on the transmitter side, to test the capabilities of the receiver.

  • $\begingroup$ $E_s/N_0$ happens at the receiver, not the transmitter (the transmitter can relatively safely be assumed to be noise-free). The symbol rate is fixed (or, to be chosen from a fixed list) by the standard, so you can't vary that, either, if you're using DVB-S2 specs. $\endgroup$ Feb 9, 2022 at 10:23
  • $\begingroup$ by the way, the sample rates are all wrong, and you must not use a throttle in the same graph as a USRP – the GRC log window will alert you to both! $\endgroup$ Feb 9, 2022 at 10:34
  • $\begingroup$ @MarcusMüller, thanks for the response! In this setup (Data -> GNU Radio -> USRP), where is the symbol rate being set? It seems to me like the sample rate is set by the USRP, so then if I know the samples per symbol (2 for QPSK for example), will I know the symbol rate? Thanks! $\endgroup$ Feb 9, 2022 at 15:45
  • $\begingroup$ that sounds about right; note that the throttle really does nothing to the digital signal, just artificially slows down computations, and you can't have that here, it competes with the USRP. $\endgroup$ Feb 9, 2022 at 15:50


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