A sampling rate of 2M is supporting a sine generation of 2.5G

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

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On Wed, Feb 1, 2012 at 11:11 PM, Ebtisam [email protected]
wrote:

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