Sine sweep in matlab

How do i create a dataset which has a sine wave which is swept a hz to b hz within the time t.

Answer 1

[Image Analyst]

If you have the Signal Processing Toolbox look in the help for chirp():

chirp
Swept-frequency cosine
Syntax
y = chirp(t,f0,t1,f1)
y = chirp(t,f0,t1,f1,'method')
y = chirp(t,f0,t1,f1,'method',phi)
y = chirp(t,f0,t1,f1,'quadratic',phi,'shape')

[James]

could you give an example ?

[James]

it doesn't provide a dataset

[Image Analyst]

Did you try to adapt the example in the help:

a = 1
b = 150;
t = linspace(0, 0.1, 300);
y = chirp(t, a, t(end), b);
plot(t, y, 'b*-');
grid on;

[Mahmoud Khadijeh]

I have question please,

The amplitude is equal to 1 when the time = 0.

Can we modify this code so the amplitude starts with 0 at t=0?

Thanks in advance!

[Image Analyst]

@Mahmoud Khadijeh did you try just subtracting it from 1?

a = 1

a = 1

b = 150;
t = linspace(0, 0.1, 300);
y = 1 - chirp(t, a, t(end), b);
plot(t, y, 'b*-');
grid on;

Otherwise you could make up your own with a vector for frequency, and use

y = sin(2 * pi * frequency .* t)

[Mahmoud Khadijeh]

Yes, subtracting it from 1 will change the entire amplitudes.. As you can see in last figures that the amplitudes are equal to 2 not 1 like the first figure.

[Mahmoud Khadijeh]

Can you pleaes help me with this code if you have the experience to do it?

This is the Logarithmic Sweep Rate equation that I am trying to implement:

The starting and ending frequencies are f1 and f2 , respectively.

The sweep rate in octaves per time is R

Thank you in advance!

[Image Analyst]

f1 = 
f2 = 
R = 
t = linspace(0, 5*pi, 2000);
frequency = linspace(f1, f2, length(t));
y = sin(2 * pi * frequency .* (-1 + 2.^(R * t)) / (R*log(2)));