Re: [Discuss-gnuradio] Re the spectrum estimation toolbox

[Martin Braun]

On 04/10/2014 12:12 AM, Ruecan wrote:
> Hello GR,
> 
> I have multiple questions re the gr-specest toolbox:
> 
> 1/ Is there any MTM estimator block for GRC

Yes!

> 2/ Can anyone explain to me the figures in
> https://www.cgran.org/wiki/SpecEst related to Cyclostationarity-Based
> Modulation Classification. I am actually confused aren't they inverted (QPSK
> and BPSK) because it is in the QPSK that you find components on the Im. axis
> not in the BPSK. Any explanations is well appreciated.

This is not IQ, it's frequency and symbol rate on the axes.

> 3/ The README file talks about how to tune the update rate (sample_rate /
> block_len) however I tried to decrease it to almost 15, sample rate = 32k
> and block_len = 2048 and even I tried to have an FFT size 256, I always get
> the plot stuck and is hardly updating. No zoom is possible after I run the
> estimator.
> And after I run that, I cannot Pause nor close. I just have to kill the
> process. 
> Am I missing something or some tuning.

Not sure here, but I know guys at CEL have been working to update the
toolbox to 3.7, maybe that'll fix it.

Martin