In gnuradio-companion I connected output of a "PSK Mod" directly to a "PSK Demod" input. Both of the blocks have the same initializations,
Number of Constellation Points:2
in PSK Demod other properties are as follows:
The output of the PSK Demod is fed into "UHD:USRP Sink" with a zero center frequency after applying some type conversion blocks, "UChar To Float" &
"Float To Complex". I connect an external oscilloscope, i.e. not in PC, not a GRC block a real one, to the output of the USRP to observe what I have after appyling PSK mod
and demod. As the output of the process, I have a completely different signal from I generated in the beginning.
I also checked what happens if I directly feed the actual signal to the "UHD:USRP Sink", I got a signal nearly same as the original one, that is as expected, great.
Another surprising thing, when I apply the output of the "PSK Mod" to the "UHD:USRP Sink" and observe the output of the USRP1 output, constellation points number is 2, although I see BPSK format, 180 degree phase shift in the signals as I expected, I see 100 kHz baseband signal frequency converts into 62.42 kHz, oscilloscope says so :), Samples / Symbol rate is 8.
What might be the problem?