0
$\begingroup$

I am currently trying to realize this block diagram in Gnu Radio Companion:

OQPSK modulation and demodulation

Before using a file source block with the binary I want to send, I plan on just using a vector with an alternating 1,0 pattern (e.g., [1,0,1,0....])

From there for the Serial to Parallel piece which block would I use? Does such a block exist; if so I am not able to find it. The way I picture this is that the first bit would go to the I multiply portion and the next bit to the Q.

[1,0,1,0] [1 -> I] [0 -> Q] [1 -> I] [0 -> Q]

Is that the right understanding?

Or would it be that, let's say 8 bits were transmitted at the same time to I and Q simultaneously and the Q branch would be on a delay?

Edit: I think that I don't need to do that serial to parallel at all.

Current setup: enter image description here

enter image description here

Something might be a little off though

enter image description here

$\endgroup$
3
  • $\begingroup$ I believe that with Offset QPSK, that the T/2 delay is naturally implemented by picking out the even-indexed bits and routing those to the in-phase (I) component and routing the odd-indexed bits (which are delayed by T/2, compared to the even bits) to the quadrature (Q) component. so it's a demultiplexing operation, no need to do "serial-to-parallel" and then apply T/2. I think your understanding is right. $\endgroup$ Commented Sep 10, 2021 at 18:49
  • $\begingroup$ I edited the comment above. I think it is possible just to multiplex but I still think I have something slightly off. $\endgroup$
    – dee_es_pee
    Commented Sep 12, 2021 at 1:56
  • $\begingroup$ I am no QPSK expert, but i have recently been thinking out loud about Offset QPSK, which I think is elegant . another and another. $\endgroup$ Commented Sep 12, 2021 at 4:22

0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Browse other questions tagged or ask your own question.