When USRP down convert the passband signal, does it perform phase estimation? Or in other words, does the phase of the sin wave from the local oscillator lock to the phase of the incoming signal? Phase is needed in coherent demodulation. I just want to know where it is performed in the USRP and GNU radio. I conjecture that the USRP does not estimate the phase and the demodulator does phase estimation, for example, in gr_mpsk_receiver_cc. But I am not sure. -- View this message in context: http://www.nabble.com/Does-USRP-do-phase-estimatio... Sent from the GnuRadio mailing list archive at Nabble.com.
on 2009-05-31 22:55
on 2009-06-01 00:21
Isulsz The DDC on the USRP only mixes the signal down using the CORDIC algorithm. The CORDIC only multiplies the input signal by scale values corresponding to cos and sine. The phase estimation should happen in the C++ code on the PC then. Sebastiaan