Re: [Discuss-gnuradio] QPSK basic modulator

[Karim El Defrawy]

Jason Uher wrote:
> > I checked the benchmark_tx.py it adds a preamble and a lot of data before
> > the actual payload which I don't need.
>
> I assume you are trying to do some BER measurements?  There is an
> example called digital-bert that will do that (bert=bit error rate
> tester).

Actually I am not. I just want to transmit the data using QPSK and 
capture it by an oscilloscope. I want to see how I can control the 
frequency offset, phase and amplitude by playing with these parameters 
at the transmitter and how this will affect the sent signal.

There are small errors introduced by the radio and I want to study those.


> If you have some other goal in mind, I would suggest examining the
> digital_benchmark_*.py files and extracting the blocks you need into a
> new python file that simply modulates and sends (basically skip the
> packet_{sink|source}).  Keep in mind that there would be no
> synchronization at the receiver with such a setup and that when you
> repack the bytes there may be an offset that you have to account for
> during processing.

At this point I don't care about demodulation, but you are right. I 
probably will later.

Thanks a lot Jason. I will start doing that too.

> Jason