On Mon, Jul 18, 2005 at 06:10:44PM -0700, Angilberto Muniz Sb wrote:
> Matt
>
> While playing with "test_usrp_standard_tx[rx].cc"
> setting
> "-c" flag, I was expecting the folloing:
>
> x x x
> x x x
> x x x
> x x x
> x x x ......
>
> But its not what I am getting.
>
> If I change the code that deal with the "counting
> flag" as:
>
> if (counting_p){
> for (int i = 0; i < N; i++) {
>
> counter += delta;
>
> buf[i] = host_to_usrp_short (counter & xffff);
>
> if (i < N/2) delta = 1;
> else delta = -1;
> }
> }
>
> I would expect:
>
> x x
> x x x x
> x x x x
> x x x x
> x x x ......
>
> I dont get it either...
These are *very* low frequeny ramps. They are most likely not getting
through the transformer on the basic tx board.
> Am I correct in my assumptions?
More or less.
> When I watch the DAC on the scope or when I plot it
> whith Matlab I see some breakups like its outputting
> in bursts... Is this the correct/expected behavior?
Should be continuous, but it will be hard to see.
You'll be much better off using gnuradio-examples/python/usr/usrp_siggen.py
If you're getting underruns, use a bigger value for the interpolation
factor. Try using -i 128. That will result in 1MS/sec (complex)
across the USB.
> Lets suppose I want to generate 10khz sin/cos wave --
> can "test_usrp_standard_tx.cc" handle it whith some
> modifications?
Note again that you won't be able to see a 10kHz sine wave at baseband
due to the transformer. You can use the --duc-freq=1M option to put
it up at 1MHz.
[EMAIL PROTECTED] usrp]$ ./usrp_siggen.py --help
usage: usrp_siggen.py [options]
options:
-h, --help show this help message and exit
--sine generate a complex sinusoid [default]
--const generate a constant output
--gaussian generate Gaussian random output
--uniform generate Uniform random output
-iINTERP, --interp=INTERP
set fgpa interpolation rate to INTERP
-fFREQ, --freq=FREQ set waveform frequency to FREQ
-aAMPL, --amplitude=AMPL
set waveform amplitude to AMPLITUDE
-oOFFSET, --offset=OFFSET
set waveform offset to OFFSET
-cFREQ, --duc-freq=FREQ
set Tx DUC frequency to FREQ
-nNCHANNELS, --nchannels=NCHANNELS
set number of output channels to NCHANNELS
-mMUX, --mux=MUX set output mux register
Eric
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