How to get constellation after demodulation

GNU Radio
1

Hello,

I receive data from USRP and demodulate them, then I can have the
constellation. But, I can’t find a way to join blocks, so they can show
a
result. I need some help concerning the scheme I have to implement to
get
my constellation.
Thanks in advance.

Best Regards,
Azza.

2

I’m assuming you want to visualize the symbols after synchronization
but before decision making. At the moment this is a pain, because the
fine phase adjustment and the decision making are performed in the
same block (constellation_receiver). What you want is the fourth
optional output of the constellation_receiver block. Unfortunately
this output is not available in any of the hierarchical demodulation
blocks (because hierarchical blocks can’t have optional outputs yet).
This means that if you want to do it in grc you won’t be able to use
one of the straightforward demodulation blocks, rather you’ll have to
put all the synchronization blocks in there independently.

When I want to do this, I do it in python, and hackishly connect
directly to the ‘constellation_receiver’ block that is inside the
demodulation block.

i.e. tb.connect( (my_demodulation_block.receiver, 4),
my_visualization_block)

Ben

On Fri, Mar 22, 2013 at 2:53 AM, Azza Ben Mosbah

3

Take a look at gr-digital/python/generic_mod_demod.py for an example
of the kind of signal-processing blocks that you’ll need.

On Fri, Mar 22, 2013 at 10:30 AM, Azza Ben Mosbah

4

dear Azza Ben

Hello,

I am pandiyan from tirupur. how can create your link.

what type of payment type or advance,

Best Regards,

pandiyan.