Envelope function of a signal

I have two sine signal with me and I wanted to find an envelope of both the signal. Could anyone tell me how to do that?

Answer 1

[Star Strider]

Use the envelope function.

t = linspace(0, 1, 1E+3);
s = sin(2*pi*t*5) .* sin(2*pi*t*100);

[senvu,senvl] = envelope(s, 10, 'peak');

figure
plot(t, s, 'DisplayName','Signal')
hold on
plot(t, senvu, '-m', 'LineWidth',2, 'DisplayName','Upper Envelope')
plot(t, senvl, '-c', 'LineWidth',2, 'DisplayName','Lower Envelope')
hold off
grid

.

[vani]

Its showing error like below

Index in position 1 is invalid. Array indices must be positive integers or logical values.

Error in myenvelope>envelope (line 159)

t=linespace(0,1,1E+3); (for this line)

[Star Strider]

This is misspelled:

t=linespace(0,1,1E+3); % (for this line)

↑

Because of that, MATLAB does not recognise it as a function, and considers it a variable, throwing the error.

If you copy and paste my code exactly as I wrote it (perhaps using your own ‘s’ function instead), it should run without error.

.