Problem with qt constellation block

GNU Radio
1

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

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2

On Mon, May 19, 2014 at 2:46 PM, zielalaoui [email protected]
wrote:

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