Hello, I am working on a real time voice Tx/Rx using GNU Radio as software and a USRP E110. I'm trying to do a QPSK Modulation and I have consulted several models and forums and it seems everything is okay, however at the moment of receiving signal, the audio on the receiver is breaking up, and I want the audio sounds good. I thought it might be because of some errors in synchronism and carrier recovery, so I added the block MPSK Reciever, without any changes in the audio output. Is anything I am missing? or Is any calculation or number wrong?
Could it be because of lack in processing? because I've tried the same model with GMSK mod/demod blocks and the voice sounds good. I've attached the flowgraphs of the Tx and Rx side for a better understanding.
I really appreciate your help and I look forward your reply.
Regards.
Marqo
P.S. I've also read that at the moment of involving blocks that work with hardware (USRP Sink/Source) I have to skip the Throttle blocks, is that true?
QPSKRx.jpg
QPSKTx.jpg