Envelope detection in MATLAB

1. What does envelope detection do?
2. How do you find the envelope of a signal?

What does envelope detection do?

An envelope detector can be used to demodulate a previously modulated signal by removing all high frequency components of the signal. The capacitor and resistor form a low-pass filter to filter out the carrier frequency.

How do you find the envelope of a signal?

In the EMD algorithm, the upper and lower envelopes of signals are obtained by using two steps: 1) identify all the local extrema; 2) interpolate between extrema by a cubic spline [9]. The interpolative envelope includes the upper and lower envelopes.