Re: [Discuss-gnuradio] Spectrum_sense of a smaller banwidth

[Eric Blossom]

On Tue, Mar 10, 2009 at 10:48:10AM -0700, David Adrian wrote:
> Thanks for the reply Eric, here is what I have now:
> 
> #!/usr/bin/env python
> 
> from gnuradio import gr, gru, window
> from gnuradio import usrp
> 
> from gnuradio.wxgui import stdgui, fftsink, scopesink
> import wx
> 
> class topBlock(gr.top_block):
>     def __init__(self):
>         gr.top_block.__init__(self)
> 
>         fftsize = 256
>         udecim = 256
> 
>         mywin = window.blackmanharris(fftsize)
>         fft = gr.fft_vcc(fftsize, True, mywin)
> 
>         signal = usrp.source_c(0,udecim)    # signal from Basic RX, 
> decimation=256
> 
>         ss2v = gr.stream_to_vector(gr.sizeof_gr_complex, fftsize)
>         v2ss = gr.vector_to_stream(gr.sizeof_gr_complex, fftsize)
> 
>         f_sink = gr.file_sink(gr.sizeof_gr_complex,"output.dat")
> 
>         self.connect(signal, ss2v, fft, v2ss, f_sink)
> 
>         # Do stuff with fsink.data()
>         
> 
> def main():
>     print "Initilizing.."
>     tb = topBlock()
>     print "Flowgraph start.."
>     tb.start()
> 
>     print "Exiting.."
> 
> if __name__ == "__main__":
>     main()
> 
> But the output.dat file is empty. What I want to do here is to
> calculate the fft of a bunch of samples and from there to extract
> the bin with the maximum value in order to be able later to "follow"
> that signal in a aprox 200 Hz bandwidth

> Adrian
> 

Use tb.run() instead of tb.start().
As written this exits immediately.

Eric