Re: [Discuss-gnuradio] Spectrum sensing Simulation Only

[Martin Braun]

Tadilo,

please stick to the mailing list.

On 07/30/2014 08:23 PM, Bogale, Tadilo Endeshaw wrote:
> Hello Martin 
> 
> Thank you for the help. I try to run "specest_noisy_sinusoid_mtm.py" (Python 
> script is also okey for me). However it does not run "it says no module 
> specest".

Did you install gr-specest?

> 
> My goal is is to write a simple python or gnuradio code to perform the 
> following task 

That's really simple. In gr-specest, the "Welch" blocks pretty much do
that. Even without, you can easily click that together in GRC.

M
> 
> I have the following variables
> 
> NFFT=1024
> Nav=512
> ampl=1
> seed=1
> Sampling_rate= 10k
> 
> 1. Generate any real time signal (This could be done by using 
> "gr.noise_source_f (gr.GR_GAUSSIAN, ampl, seed1)).
> 
> 2. Insert throttle to control the sampling rate (i.e., gr.throttle(1, 
> Sampling_rate))
> 
> 3. Compute the FFT (even without windowing) (i.e., NFFT samples at a time) 
>     
>     Let me assume that after I compute FFT I got "x" vector of size NFFT 
> 
> 4. Compute the square magnitude (This could be done by using 
> gr.complex_to_mag_squared(NFFT))
> 
> i.e., in matlab y=abs(x).^2
> 
> 4. sum the first and second Nav samples 
>  
> i.e., av1=sum(y(1:512)) and
>        av2=sum(y(513:1024))
> 
> 5. Then display "av1" and "av2" in some GNUradio GUI continuosly.
> 
> Note that in matlab (without GUI it is very easy task)
> 
> And I feel that there should be some simple approach to do it in GNUradio 
> 
> Thank you again for your help
> 
> ---
> Tadilo Endeshaw
>  Postdoctoral Researcher
>  Institut National de recherche Scientifique
>  Centre Energie Matriaux Telecommunications
>  Place Bonaventure,
>  800 de la Gauchetiere Ouest, Suite 6900
>  H5A 1K6
>  Montreal, QC
>  Canada
>  E-mail : address@hidden
>           address@hidden (private)
> Personal home page: https://sites.google.com/site/tadilomypage/
> ________________________________________
> From: address@hidden address@hidden On Behalf Of Martin Braun address@hidden
> Sent: July 30, 2014 10:01 AM
> To: address@hidden
> Subject: Re: [Discuss-gnuradio] Spectrum sensing Simulation Only
> 
> On 07/30/2014 03:37 PM, Tom Rondeau wrote:
>> The easiest way to average is to use the single_pole_iir_filter to
>> smooth out the data stream. But note that you're coming out of the FFT
>> block as a vector. You can set the vector length of the single pole IIR,
>> but I'd have to review exactly what that means mathematically. It
>> probably smooths the entire vector as one as opposed to smoothing over
>> index i in each vector. You might have to play around with that.
> 
> gr-specest might help you with that (pybombs install gr-specest, or
> https://github.com/kit-cel/gr-specest).
> 
> M
> 
> 
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