Envelope of a Signal

Envelope of a Signal

This tool finds the upper and lower envelopes of a signal. It selects the data points with the maximum possible area for the upper envelope and the minimum possible area of the lower envelope. Based on this method, it only works well with concave upper envelopes and convex lower envelopes. Example file is provided.

function [xe,ye]=Envelope(x,y,type,N)

input:

x: x vector of the signal

y: y vector of the signal

type: 'upper' for upper envelope and 'lower' for lower envelope

N: number of data points of the envelope

output:

xe: x vector of the envelope

ye: y vector of the envelope