Re: [Discuss-gnuradio] Display for the I/Q channels of a digital modulation with gnuradio

[Ilia Mirkin]

On Thu, 2006-03-16 at 11:10 +0100, EVENNOU Frederic RD-TECH-GRE wrote:
> Hi,
> 
> I'm starting to use the GNUradio platform for digital communication
> tests.
> I'm digitizing a radio signal with the GNUradio platform and processing
> it with my computer to extract the I/Q channels (QPSK), but I'm
> wondering if it is possible to display the constellation of this signal
> thanks to functions similar to fftsink (for the FFT of a signal) or
> scopesink (for a time trace of the signal) ? Does such a function exists
> in GNUradio (eg iqsink) ?
> Thank you for your help.

Once you have the I and Q separated, you can attach both of them to the
scopesink, (i.e. bla.connect(i, (scope, 0)) and bla.connect(q, (scope,
1)) ) and then select X vs Y for plotting, which will plot the I signal
vs the Q signal, which ought to show you the constellations if your
decoding is accurate.

  -Ilia