Re: [Discuss-gnuradio] A medley of questions

[Eric Blossom]

On Wed, Mar 14, 2007 at 09:47:20PM -0400, Steven Clark wrote:
> Plots of USRP decimation woes:
> input is GMSK waveform @ ~30ksym/sec, BT = 0.35, no noise added
> using decimation rate of 16:
> http://img339.imageshack.us/img339/4467/d16cz9.jpg
> top plot is complex baseband, bottom plot is amplitude of top plot
> some amplitude variations noticeable, but fairly minor.
> 
> using decimation rate of 256:
> http://img256.imageshack.us/img256/2850/d256qh2.jpg
> heavy amplitude variations.
> zoomed in version of previous plots:
> http://img490.imageshack.us/img490/6528/d256zoomedku7.jpg
> 
> Still confused as to what is going on here...

Steve, what's the real amplitude of the received baseband signal?
I suspect that you are normalizing to 1.  Can you regenerate the plots
without normalizing so that we've got an idea of the values coming
across the USB.

Eric