Perhaps the digital values are all zero for benchmark rate?
On Wed, Dec 18, 2019 at 7:02 AM voonna santosh via USRP-users <
usrp-users@lists.ettus.com> wrote:
> One more thing to add:
> If I run benchmark_rate with out any modifications, then the output in
> scope if perfect.
>
> I have added the following code snippet to configure the tx_freq and there
> is nothing observed in scope.
>
> if (vm.count("tx_freq")){
> for(size_t ch = 0; ch < tx_channel_nums.size(); ch++) {
> std::cout << boost::format("Setting TX Freq: %f MHz...") %
> (tx_freq/1e6) << std::endl;
> uhd::tune_request_t tune_request(tx_freq);
> if(vm.count("int-n")) tune_request.args =
> uhd::device_addr_t("mode_n=integer");
> usrp->set_tx_freq(tune_request, tx_channel_nums[ch]);
> std::cout << boost::format("Actual TX Freq: %f MHz...") %
> (usrp->get_tx_freq(tx_channel_nums[ch])/1e6) << std::endl << std::endl;
> }
> }
>
> Command used for testing: ./benchmark_rate --args="addr=192.168.40.2"
> --channels="0" --tx_rate 50e6 --tx_freq 20e6 --duration 50
>
>
> NOTE: I am using Agilent E4402B to analyze the spectrum (9KHz to 3 GHz)
>
> Thanks,
> Santosh
>
>
>
>
>
> On Wednesday, December 18, 2019, 11:20:10 AM GMT, voonna santosh <
> santu_voo...@yahoo.com> wrote:
>
>
> FYI:
> Does something like tx_waveforms[1] output a signal at the expected
> frequency?
> - Yes, both tx_wavefrom and benchmark_rate works fine. I took benchamark
> rate and extended it to get tx_freq configured. This is not working.
>
>
> With respect to the 10MHz, this is the frequency of signals used to
> discipline the internal timebase to an external source. I wouldn't expect
> artifacts from this signal to be present at the TX port under normal
> circumstances. Are you using an external reference? What about the GPSDO?
> - Since my base line is benchmark_rate, the default frequency is 10MHz
> which always works fine. But when I change the frequency, thats when I see
> the issue. I couldn't trace where it is getting set, but it does. Can you
> please let me know where in the code, it sets the frequency to 10MHz ?
>
> BR,
> Santosh
>
>
>
>
>
> On Tuesday, December 17, 2019, 11:45:29 PM GMT, Sam Reiter <
> sam.rei...@ettus.com> wrote:
>
>
> Does something like tx_waveforms[1] output a signal at the expected
> frequency?
>
> What are you using to measure the frequency output?
>
> With respect to the 10MHz, this is the frequency of signals used to
> discipline the internal timebase to an external source. I wouldn't expect
> artifacts from this signal to be present at the TX port under normal
> circumstances. Are you using an external reference? What about the GPSDO?
>
> [1]
> https://github.com/EttusResearch/uhd/blob/master/host/examples/tx_waveforms.cpp
>
> Sam Reiter
> Ettus Research
>
>
> On Mon, Dec 16, 2019 at 9:01 AM voonna santosh via USRP-users <
> usrp-users@lists.ettus.com> wrote:
>
> Hi There,
> I have bench marked X300 against my development PC. Then I took
> benchmark_rate code and modified a bit. Everything works fine except
> setting the center freq.
> When ever I set the center frequency, there is no error returned by the
> call. But when I transmit the data, it doesn't appear in scope. Whenever I
> remove the code to set the center frequency, things work fine and I cann
> see a spike at 10Mhz which is default frequency I guess. Any clues?
>
> std::cout << boost::format("Setting TX Freq: %f MHz...") % (freq/1e6) <<
> std::endl;
> uhd::tune_request_t tune_request(freq);
> //usrp->set_tx_freq(tune_request, 0); - This line also doesn't work
> usrp->set_tx_freq(freq, 0);
> std::cout << boost::format("Actual TX Freq: %f MHz...") %
> (usrp->get_tx_freq(0)/1e6) << std::endl << std::endl;
>
> Thanks and Regards
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