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jgaeddert / liquid-dsp

digital signal processing library for software-defined radios
http://liquidsdr.org
MIT License
1.9k stars 443 forks source link

Question regarding flexframegen #225

Closed mryndzionek closed 3 years ago

mryndzionek commented 3 years ago

I'm trying to use the flexframegen object with different modulation schemes. When I look at a IQ waterfall the signals look very similar regardless of the modulation scheme used (same, constant payload): BPSK bpsk_

QPSK qpsk_

ASK2 ask2_

Is this supposed to be this way? BPSK and ASK2 look almost the same...

pfeatherstone commented 3 years ago

BPSK and ASK2 are the same

pfeatherstone commented 3 years ago

Somewhere in the liquid docs there will be some pictures of the different constellations. There you will see BPSK is the same as ASK2, QPSK is the same as PSK4 (maybe there is a phase difference of pi/4, not sure)

mryndzionek commented 3 years ago

Okay, I've found it: https://liquidsdr.org/doc/modem/ Thanks!