Tx_sampless.cc not working fine...?

casper_the_ghost · March 31, 2010, 5:58pm

Hi,
Â
Â I have some issue with tx_samples.cc and the GRC.
Â Â
Â when i send the file containing complex I&Q samples from GRC
Transmitter side : File Source —>USRP2_sink(interp=16, f=1.8G)
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
|–>FFT_sink(avg=yes)
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
Receiver side:Â usrp2_fftsink.py (decim=16,f=1.8G)

I get perfect frequency plot matching exactly as seen in the transmitter
side.

But
when i use tx_samples.cc (interp=16, f=1.8G, -r)Â to transmit the same
file. I get the almost same frequency plot with lot of dissortion, I
have checked all the available parameters in the tx_samples.cc but in
vain.

I have also , python generated code top_block.py by the
GRC for the above function with the tx_samples.cc , both are sending
32bit floating complex values to usrp2_sink…, how come their results
are different…? even though keeping all the parameters same for both
of them…!

(Tim, i posting with a new subject)

Thank you
KRISHNA S

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casper_the_ghost · March 31, 2010, 7:07pm

What about the gain setting? In grc, the gain setting defaults to 0 dB,
this is not the case for tx_samples, try adding -g 0 to the options.

-josh