Re: freqz issue

[Laurent HAAS - F6FVY]

Hi Kai et al.

Thanks for your reply.

Le 10/01/2020 à 03:09, Kai Torben Ohlhus a écrit :

> I am a bit lazy to go deep into your issue (not my domain), but a
> minimal working example would be
>
>    y = ones (1, 5000);
>    freqz(y(1:5000),1,[-4E6:.01E6:4E6],2.5E6);
>
> Thus what is the `y` you are trying to work with?

y are I/Q sample (complex) from a radio receiver.

And your basic example, opened my eyes.

Apparently, at least when plotting spectrum, Octave freqz can *only* use 
real data (not complex), while Matlab freqz can handle complex data, and 
plot correct spectrum (not symetrical around DC).

Being a total newbie in Octave, I can't say if it has to be considered 
as a known limitation of Octave, or a bug concerning "Matlab 
compatibility ? I couln't find any bug report about that.

In all cases, the spectrum output can't be plot identically to Matlab 
this way.

Thanks again and rgds

Laurent

--

I never lose. I either win or learn - Nelson Mandela