Forum: help

Strange behavior in the chirp block [ Reply ]
By: Fabien Millioz on 2010-03-24 11:56

figures.png (21) downloads

Hi,

The chirp block gives strange results on a simple chirp.

Matlab code:

fs=1600;
nb=16;
chirp=0.9*sin(2*pi*cumsum(linspace(0.1,0.4,1e5)));
chirp=0.9*sin(2*pi*(0.1*[1:1e5] + 0.3/2*1e-5*[1:1e5].^2));
wavwrite(chirp,fs,nb,'chirp.wav');

--

mpd -D dic_chirp.xml -v -n 5 chirp.wav chirp_mp.bin
mpview chirp_mp.bin tfmap.flt

--

In Matlab
mpview('tfmap.flt');

I expected to get chirped atoms along the frequencly line visible on the spectrogram.

Figures:
spectrogram(chirp, hanning(511),255,1024,fs)
results of the mpview command and a zoom
The "vertical" atom is visible on the matlab figure and disappear only during the png export.

Fabien