Fwd: time_recov and freq_recov in generic_mod_demod

GNU Radio
1

Ada,

As I looked up from the documents, it was said that the signal after the
usrp source at the receiver, is baseband signal, whose central
frequency
is around 0 Hz, and already take off the carrier frequency. But in the
demodulation, there are still freq_recov and time_recov block. >Are they
at
the symbol level?

Yes and there is always a freq-difference between Tx and Rx LO due to
this
there will always be some freq-offset

http://gnuradio.org/redmine/projects/gnuradio/wiki/FAQ#Why-is-there-always-a-frequency-offset-when-transmitting-from-one-USRP-to-another

I’m quite confused with how the benchmark, actually the demodulation in
generic_mod_demod.py works. When does the carrier frequency is >taken
off?
In USRP. Timing recovery for compensating timing-offset, Freq-Recovery
for
freq-offset.

http://gnuradio.org/doc/doxygen/classdigital__pfb__clock__sync__ccf.html
http://gnuradio.org/doc/doxygen/classdigital__fll__band__edge__cc.html

-Adeel