Re: [Discuss-gnuradio] Re: FM data available

[Stephane Fillod]

On Wed, Feb 19, 2003 at 10:29:27AM -0800, Eric Blossom wrote:
> > Sadly enough, my Duron 1GHz is a bit slow too on data crunching, especially
> > using generic code for FIR filters. So I wrote fir_SCC optimization (for
> > GrFreqXlatingFIRfilter) using 3DNow!Ext, and it improves a bit:
> > 
> > (address@hidden:examples)$ ./benchmark_dotprod_SCC
> >    generic: taps:  256  input: 4e+07 cpu: 107.360  taps/sec:  9.538e+07
> >  3DNow!Ext: taps:  256  input: 4e+07  cpu: 29.710  taps/sec:  3.447e+08
> 
> Excellent!

Some new numbers (SSE still WIP):

(address@hidden:examples)$ ./benchmark_dotprod_SCC
   generic: taps:  256  input: 4e+07 cpu: 107.360  taps/sec:  9.538e+07
 3DNow!Ext: taps:  256  input: 4e+07  cpu: 28.640  taps/sec:  3.575e+08
    3DNow!: taps:  256  input: 4e+07  cpu: 50.920  taps/sec:  2.011e+08

Remark: SCC is half the speed of FFF dotprod because Complex taps are involved.

> > I'll submit a patch when I have regular 3DNow! and SSE done.
> > For GrRealFIRfilter, what to you think is best? optimize fir_FSF or use
> > fir_FFF with convert_FS ?
> 
> I'll get back to you later.

The best solution, which I implemented already, is to not use conver_FS,
but make use of float_dotprod_xxx, and cast the result to a short.
Unfortunately, the GrRealFIRfilter speed boost (even with 529 coeffs)
is not as noticeable as GrFreqXlatingFIRfilter (which runs at high
sampling rate).

BTW, is there a mean to gather some stats about the various sig
process figures in the chain? This would to know where most of the CPU cycles 
are spent.

> > I have another request for data file.
> > Is it possible for you to provide me a data file (16-bit, 20MS/s, 
> > size<100Mo),
> > containing Narrow FM, USB, and AM. Something like a Ham portion plus
> > air-band for the AM would be fine. In need to have data for *each* of
> > these modes to be able to test all the demodulators.
> 
> I don't have this data.  Perhaps someone else can come up with it.

Wouldn't it be possible for anyone with a microtune board to tune to 144MHz
and then sweep the ham band?  Some samples around 125MHz would be neat too.

Cheers
Stephane