Playing a varying frequency in Hertz in matlab?

Question

I have some matlab code which produces frequency (in hertz) of a sound over 5 seconds. The code as it stands outputs 100 samples per second, and I want to play the 5 second block to see what this sounds like, but I'm having issues with sampling rate and sound / soundsc commands.

My frequency oscillates (data here ) and I'd be very grateful if someone could help me convert this data into some kind of real-time approximation of what it should sound like.

Answer 1

Something like this may be helpful

Fs=2000; %sample rate, Hz
t=0:1/Fs:5; %time vector
F=298+sin(2*pi*t);  %put your own F here

S=sin(2*pi*F.*t);  %here is the sound vector

%visual check
figure(1);
plot(t,S)
figure(2);
plot(t,F)

%listen
wavplay(S,Fs)

This is like FM modulation, but different. If you have an Fold vector with a different sample rate, you can convert it with the command

F=interp1(told,Fold,t);  %told and Fold are F at a different sample rate 
%check it
plot(told,Fold,t,F)

Answer 2

First, your sampling rate should be at least twice the maximum frequency according the Nyquist–Shannon sampling theorem.

Next, you need to generate a sinusoid:

Signal = sin(2*pi*Phi);

where Phi is the phase corresponding to the desired frequency pattern, which is simply an integral of the frequency (which you can do numerically or analytically).