How can i set the plot values of a specgram.

I have a DTMF signal, that i realized a specgram of it. But i dont know how to set my own values to it, i want to put this code to this signal.

title("Spectograma semnalului DTMF")
xlabel("Timp[ms]");
ylabel("Frecventa[Hz]");
axis([0, 800, 0, 2000]);
xticks(0:200:800);
yticks([800, 900, 1000, 1100]);
grid on;

Answer 1

[Hiro Yoshino]

Short Time Fourier Transform?

stft(x,fs,'Window',kaiser(256,5),'OverlapLength',220,'FFTLength',512);

see: https://jp.mathworks.com/help/signal/ref/stft.html

[Peter Cristian]

No, i want my plot to look something like this:

[Hiro Yoshino]

It seems that it is just about your setting for that function.

You can remove the "overlap" and try making the window narrower.

[Hiro Yoshino]

If you want to suppress areas of no-interest, you can replace those values with something else by giving a threshold to it:

x(x<threshold) = 0;