How can I use the chirp function to create a linear sine sweep from a given starting and ending frequency within a given time frame?

How could I, for example, make a 3 second sine sweep starting at 40 Hz and ending at 10 kHz?

The examples given in the help section for chirp have not been useful.

Answer 1

[David Barry]

% create time signal
freqSamp = 1e6;
tStart = 0;
tEnd = 3;
t = tStart:1/freqSamp:tEnd;

% create swept sine
freqStart = 40;
freqEnd = 1e4;
phaseInit = -90;
method = 'linear';
y = chirp(t, freqStart, tEnd, freqEnd, method, phaseInit);

[Tyler Bisson]

I don't think this works unfortunately.

[David Barry]

What is the problem you are seeing?

[Atilla Golan]

It does work perfectly, I have two questions: 1- What is the role of phaseinit? I changed it to different values and nothing changed. 2- It is up-going linear, how we can make down-going one?

[Greg Dionne]

Try something like this:

t=0:0.001:2;                    % 2 secs @ 1kHz sample rate
y=chirp(t,200,1,100,'linear');  % Start @ 200Hz, cross 100Hz at t=1sec
spectrogram(y,kaiser(128,18),120,128,1E3,'reassigned','yaxis');
title('Linear Chirp: start at 200Hz and cross 100Hz at t=1sec');