Hello Ayaz,

UHD will log to standard out by default. You should be seeing it in the
console section of the GNU Radio Companion, at the bottom.

Multiplying by 500 will almost certainly lead to the signal clipping at the
DAC, completely corrupting your signal. The USRP Sink block expects values
between -1.0 and 1.0. The sample rate of 32kHz is very low. It should work,
but the general guidance is to use a somewhat higher rate as this helps
lessen the impact of the FPGA's filters on your passband signal.

Have you observed any signal from the USRP on your spectrum analyzer?
Starting with uhd_siggen_gui and making sure your spectrum analyzer is
setup correctly may be the best place to start, then your own GNU Radio
flowgraph with just the signal source going into the USRP Sink, then add
the OFDM modulation once all the rest is working.

Regards,
Derek


On Mon, Jun 11, 2018 at 9:47 PM, Ayaz Mahmud <ayazmah...@hotmail.com> wrote:

> Hi Derek,
>
>
>
> Thanks for pointing, I initially thought as the throttle was connected to
> WX GUI FFT it won’t affect the USRP sink.
>
>
>
> But the issue does not get resolves even after the throttle is removed. I
> tried increasing the gain to 30 and adding a multiply constant of 500 after
> the OFDM Mod block.
>
>
>
> As a beginner I did not knew about the log file. As I check the
> documentation the file is */usr/include/uhd/utils/log.hpp* but I am not
> sure how to run/see this logging. Any document link that you can provide as
> an example?
>
>
>
> On another hand I have tried implementing the exact same flow as in the
> link https://wiki.gnuradio.org/index.php/Guided_Tutorial_
> Hardware_Considerations - “The PSK Mod with USRP sink” one. And I am
> unable to get any output in spectrum analyzer as shown.
>
>
>
> Thanks,
>
> Ayaz
>
>
>
> *From:* Derek Kozel <derek.ko...@ettus.com>
> *Sent:* Monday, June 11, 2018 1:34:01 PM
> *To:* Ayaz Mahmud
> *Cc:* usrp-us...@lists.ettus.com
> *Subject:* Re: [USRP-users] Spectrum analyzer not picking up any signal
> from USRP-GNU Radio
>
>
>
> Hello Ayaz,
>
> Because you have hardware in your flowgraph (the B210) you should not
> include a throttle block. Check your log output, it is very likely that UHD
> is reporting underflows.
>
> I'd recommend quickly running through the GNU Radio tutorial on using
> hardware.
> https://wiki.gnuradio.org/index.php/Guided_Tutorial_
> Hardware_Considerations
>
> Also the UHD manual has some general guidance which will help you to
> understand UHD's messages.
> http://files.ettus.com/manual/page_general.html
>
> Regards,
>
> Derek
>
>
>
> On Mon, Jun 11, 2018 at 8:26 PM, Ayaz Mahmud via USRP-users <
> usrp-us...@lists.ettus.com> wrote:
>
> Hi,
>
>
>
> GNU Radio version 3.7.11
>
> USRP B210 with 1 x 2.4GHz antenna
>
> Spectrum Analyzer with 2.4 GHz antenna
>
> I am trying to transmit the below flowgraph through USRP and receive a
> signal with Spectrum Analyzer. Though the Spectrum analyzer will not be
> able to demodulate it should show a stable frequency. Unfortunately, the
> spectrum analyzer does not pick any signal while calibrated at Center Freq:
> 2.412 GHz.
>
> GNU-Radio console warning:
>
> gr::log :WARN: ofdm_mapper_bcv0 - The gr::digital::ofdm_mapper_bcv block has 
> been deprecated.
>
> gr::log :WARN: ofdm_insert_preamble0 - The gr::digital::ofdm_insert_preamble 
> block has been deprecated.
>
>
>
>
> GNU Radio version 3.7.11
>
> USRP B210 with 1 x 2.4GHz antenna
>
> Spectrum Analyzer with 2.4 GHz antenna
>
> Block diagram attached.
>
> I am trying to transmit the below flowgraph through USRP and receive a
> signal with Spectrum Analyzer. Though the Spectrum analyzer will not be
> able to demodulate it should show a stable frequency. Unfortunately, the
> spectrum analyzer does not pick any signal while calibrated at Center Freq:
> 2.412 GHz.
>
> GNU-Radio console warning:
>
> gr::log :WARN: ofdm_mapper_bcv0 - The gr::digital::ofdm_mapper_bcv block has 
> been deprecated.
>
> gr::log :WARN: ofdm_insert_preamble0 - The gr::digital::ofdm_insert_preamble 
> block has been deprecated.
>
>
>
> Where can this possibly go wrong?
>
>
>
>
>
>
>
> Thanks,
>
> Ayaz
>
>
>
>
> _______________________________________________
> USRP-users mailing list
> usrp-us...@lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>
>
>
>
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