Hello all Almost a month ago i started working on a digital communications project which involves GNUradio. I am now severely struggling to get past some errors or mismatches I am encountering in GNUradio. I am desperately in need of some expert help. I made a DQPSK modulator and demodulator using GRC. ( screenshots provided ) Gave a vector source with bits 0,1,0,1 and repeat on, on the input of psk modulator. I also used an error rate block to calculate bit error rate. Now almost everything that is appearing on the scopes is completely wrong. The bit error rate is 0.5, provided that i have added no noise.(which is max considering that we will recover 50 percent bits correctly just by chance). The scope at the psk modulator output shows four constellation points even though i am transmitting only one symbol i.e (0,1). What am i doing wrong? Can someone please be kind enough to go through the screenshots and tell me the mistake(s). Any help will be greatly appreciated. Thanks in advance.
on 2015-12-04 21:04