Re: [Discuss-gnuradio] saturation with multi_fft.py

[Eric Blossom]

On Wed, Oct 10, 2007 at 04:54:10PM -0400, address@hidden wrote:
> Well, this seems logical, and if so then we've finally stumbled on the 
> point of the matter.  So what's the fix? Is it a simple matter of 
> extending the "definitions" to other decimations in the file Brian cites?
> 
> thanks Brian and Eric,
> 
> eric

> >>
> >>Also-  this fix you are proposing- is it a simple scaling of gain that
> >>would be independent of decimation?  Because as you can see from the
> >>following figure, the amplitudes scale directly with the decimation for
> >>values above 128 on the 4 rcv rbf.
> >>
> >>www.nd.edu/~ematlis/z.gnuradio/Amplitude_vs_decimation.jpg
> >>
> >>Both rbf's produce a flat response below 128 decimation; greater than this
> >>is where the change occurs.  The standard half-band rbf does have a couple
> >>of dips but is basically flat.

OK.  In the interest of expediency, use the decimation values that
work, then complete the decimation in the host.  The reason that
there's a version that DOESN'T have the halfband is to save space.
Making anything bigger (e.g., width of CIC) is contraindicated ;)

Eric