Sorry, I wrote "coherent" meaning that the problems show up only with
signal analyses that go beyond power spectrum.
For example, the output LTE signal gives CQI=15 (max quality) with
dsp_freq=0 and variable CQI (never 15) with dsp_freq = 11.52e6 (in all
cases sampling rate is set to 23.04e6 and master clock rate is twice the
sampling rate). I do know that LTE is robust to DC offset but this is a
more general question on UHD/B210.
On Wed, Jun 5, 2019 at 4:23 PM Marcus D. Leech <patchvonbr...@gmail.com>
wrote:
> On 06/05/2019 07:12 PM, Dario Fertonani wrote:
>
> Thank you Marcus. I should have mentioned that I tried removing that line,
> with no success. With non-zero dsp_freq, the power spectrum looks OK but
> the (coherent) signal quality is terrible.
>
> OK, that's a different level of problem.
>
> You're trying to maintain coherence across more than one B210?
>
>
>
> On Wed, Jun 5, 2019 at 2:25 PM Marcus D. Leech via USRP-users <
> usrp-users@lists.ettus.com> wrote:
>
>> On 06/05/2019 05:20 PM, Dario Fertonani via USRP-users wrote:
>>
>> I'm trying to move the "DC offset" out of the main spectrum by using the
>> dsp_freq field in uhd::tune_request_t. This doesn't seem to work on
>> B210, meaning that the following code functions properly with DcOffset_Hz=0
>> but not, for example, with DcOffset_Hz=10e6. In all these tests the master
>> clock rate is large enough to fit DcOffset_Hz and the spectrum of interest
>> easily. Anything obviously wrong?
>>
>> Thanks,
>> Dario
>>
>> uhd::tune_request_t uhdTuneRequest( const double &CarrierFreq_Hz , const
>> double &DcOffset_Hz )
>> {
>> uhd::tune_request_t tuneRequest( CarrierFreq_Hz - DcOffset_Hz );
>> tuneRequest.args = uhd::device_addr_t( "mode_n=integer" );
>> tuneRequest.dsp_freq_policy = uhd::tune_request_t::POLICY_MANUAL;
>> tuneRequest.dsp_freq = DcOffset_Hz;
>> return tuneRequest;
>> }
>>
>>
>> You shouldn't need to use POLICY_MANUAL at all, since the tune_request_t
>> supports offset-tuning directly:
>>
>> https://files.ettus.com/manual/structuhd_1_1tune__request__t.html
>>
>>
>>
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>>
>
>
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