Re: calculate SNR and watch a binary file

[Markus Feldmann]

Francesco Potorti` schrieb:
> > > I can save the spectrum as a binary file.
> > > The file includes several 16 bit complex information.
> > >
> > > How to watch this with octave and calculate
> > > the SNR ?
>
> > i wrote a small script:
> > filename = "spectrum.m";
> > fid = fopen (filename, "r");
> > [val, count] = fread (fid, 100, "uchar", "native")
> > fclose(fid);
> >
> > But i want to watch the original komplex values instead of int values.
> > How to ?
>
> That depends on how the values are written to the file.
>
> > As i know my Spectrum Analyser produces I/Q Signals, so there should be
> > 2*16 bit values. Each 16 bit value is complex.
>
> What you wrote is either a typo or I do not understand it.  I suppose
> you meant that each complex value is written as two 16 bit numbers.
> If this is the case, do not use "uchar" but "int16".  Then try and see
> if you get the correct numbers, probably the real and complex parts of
> each sample.  If not, try to experiment and guess how the numbers are
> written to the file.  Or else try to find some documentation on it :)
Thanks for your Answer,

in my Spectrum there is an unknown peak in the middle of the FFT-Plot
which exists every time. I think it will be created as byproduct
of a CIC decimation(Digital Down Converter) in my analyser.
Therefor i want to manipulate this complex values, but didn't know how
to ?

Any hints ?

Regards Markus