[Discuss-gnuradio] BPSK Demod

[Kacie O'Neil]

I'm having trouble with a BPSK Modulation/Demodulation flowgraph I built 
(picture attached). I am using a Vector Source and a Constellation 
Modulator block with a BPSK default constellation object. I'm using a 
vector source because I want to verify that I can modulate and correctly 
demodulate/decode data, not just a random source. I'm trying to start 
with something simple.

For the demod, I'm following the PSK Demodulation Tutorial from the 
gnuradio wiki 
(https://wiki.gnuradio.org/index.php/Guided_Tutorial_PSK_Demodulation) 
so I have a Polyphase Clock Sync, CMA Equalizer and Costas Loop followed 
by a Constellation Decode block (using the same bpsk object as the 
constellation modulator) which I send into a file sink.

Part of my problem is that what I end up with in my File Sink is not 
what I'm expecting, so I have no way to know if the data I'm attempting 
to send is being modulated and demodulated correctly. I'm wondering if 
maybe I'm not sending data in the right format to the file sink (or any 
other block really), or if the fact that I didn't include a channel 
model or used a UHD device is creating a different result. If anyone has 
any suggestions or comments, they would be greatly appreciated!

Thanks!

Screenshot from 2017-04-12 18-30-28.png
Description: PNG image