Re: [Discuss-gnuradio] problem with qt constellation block

[Tom Rondeau]

On Mon, May 19, 2014 at 2:46 PM, zielalaoui <address@hidden> wrote:

Hi All,
I'm trying to built a system with several digital modulations. First, I
should be able to print constellations by using qt constellation block. I
started by creating a simple flowgraph with two modulations. That is my
flowgraph  <http://gnuradio.4.n7.nabble.com/file/n48338/qt_applic.jpeg>  .
I take the top_block.py file and I tried to modify it by adding new function
to switch  the null sink and the constellation block by using disconnect()
and connect() function. finally in the main function i added lock() and
unlock() functions to reconfigure the application.
the problem is when i run the modified python file the constellation graphic
appear but it conserves the first constellation representation even the
switching is happened .
what do you think about that?
should I write something to rerun the qt application?
I appreciate your help

Yes, the QT sinks keep some internal buffers, which are preserved during a lock/unlock reset event.

You could look to overload the start() function (add a bool cosnt_sink_c_impl::start() function) that calls just calls _reset() and returns block::start(). In the extreme, you could cal memset on all d_residbufs_real and d_residbufs_imag to rest them to 0, but I think just calling _reset and having the pointers appropriately update should be enough.

Tom