I was wondering if anyone has had any success in implementing OQPSK in gnuradio.

I have a working theory of expanding on the Constellation Modulator to include a custom OQPSK function.

I have already reviewed a few post, but what has been done seems too complicated.

I am wanting to learn so any reading material, etc, would be appreciated.

Feel free to comment!

  • $\begingroup$ Have you implemented something as simple QPSK already? $\endgroup$
    – A_A
    Commented Oct 22, 2019 at 9:09
  • $\begingroup$ Yes I have. Utilizing the Constellation Modulator. $\endgroup$
    – DasBoy
    Commented Oct 22, 2019 at 13:38

1 Answer 1


I think if your Constellation Modulator generates two samples per symbol and you delay the Q output by one sample, then you get OQPSK, don't you?

Demodulating is much more complicated because I and Q get mixed up due to frequency/phase offsets so you cannot just delay I to synchronize it again with Q.

  • $\begingroup$ Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center. $\endgroup$
    – ZaellixA
    Commented Oct 3, 2023 at 15:59
  • $\begingroup$ Once the synchronized IF carrier is established, then I think demodulation is pretty easy. But synthesizing a synchronized carrier is tricky and I am curious at what is the most elegant way to do that. I posted a question about this synchronization. $\endgroup$ Commented Nov 2, 2023 at 21:38

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