This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English version of the page.

Note: This page has been translated by MathWorks. Please click here
To view all translated materials including this page, select Japan from the country navigator on the bottom of this page.

Envelope Extraction Using the Analytic Signal

This example shows how to extract the signal envelope using the analytic signal.

Create a double sideband amplitude-modulated signal. The carrier frequency is 1 kHz. The modulation frequency is 50 Hz. The modulation depth is 100%. The sampling frequency is 10 kHz.

t = 0:1e-4:1;
x = [1+cos(2*pi*50*t)].*cos(2*pi*1000*t);

xlim([0 0.1])

Obtain the analytic signal. Extract the envelope, which is the magnitude (modulus) of the analytic signal. Plot the envelope along with the original signal.

y = hilbert(x);
env = abs(y);

hold on
xlim([0 0.1])

The magnitude of the analytic signal captures the slowly varying features of the signal, while the phase contains the high-frequency information.

See Also


Was this topic helpful?