On Wed, Feb 1, 2012 at 11:11 PM, Ebtisam
<address@hidden> wrote:
Hi all,
Im trying to transmit a sine wave from RFX2400 usrp, and im successful in
transmitting it. The only thing which bothers me is that im making a sine
wave from gr.vector_source_c in usrp_siggen.py with a sampling frequency of
2M = dac rate/interp rate. So, how is this sampling done or sine is sampled
at some other frequency........
Regards,
Ebtisam
Ebtisam,
I'm not sure I follow. You should be using a gr.sig_source_c to generate a sine way, not the vector source.
The sig_source takes in the sampling rate in Hz and the frequency of the sine in Hz to produce the signal. Now, to the CPU, the sampling rate is a meaningless number; all it knows is the number of samples per cycle. But the rate matters when talking to the real world -- like the USRP itself. Since the USRP is set to a rate (dac_rate/interp_rate), it expects samples coming at that rate. It's the USRP that provides the rate clocking for the rest of the system.
Tom