Re: [Discuss-gnuradio] A medley of questions

[Eric Blossom]

On Wed, Mar 14, 2007 at 10:24:10PM -0400, Steven Clark wrote:
> You're right, I was normalizing for the purposes of plotting. Here's what
> the raw complex samples look like:
> http://img490.imageshack.us/img490/3225/rawbasebandvv9.jpg
> +/- 2400 or so.
> and here's that other plot regenerated:
> http://img249.imageshack.us/img249/9520/d256unnormalizedkd4.jpg
> 
> signal is going in to RX at -10dBm, default gain setting.
> 

Steve,

Can you try this experiment?

Using your perfect samples (the ones you get with decim=8), can you
try low pass filtering them (without decimating) to the equivalent
width that you'd get with the decim=256 setting, and then plotting
them?

Maybe it's not perfectly round because with the narrower filter, we're
losing more of the sidebands.  IIRC it's only constant envelope with
infinite sidebands.

Or for a different experiment: feed in a complex sinusoid with no
modulation, and see what happens with the decim=8 and decim=256 cases.

Eric