mscohere

Syntax

msc=mscohere(x,y)

msc=mscohere(x,y,window)

msc=mscohere(x,y,window,overlap)

msc=mscohere(x,y,window,overlap,nfft)

msc=mscohere(x,y,window,overlap,nfft,fs)

msc=mscohere(x,y,window,overlap,nfft,fs,range)

[msc,freq]=mscohere(...)

Inputs

x

The signal.

Type: double

Dimension: vector

window

The window size, or the window vector.

Type: double | integer

Dimension: scalar | vector

overlap

The number of overlapping points in adjacent windows.

Type: integer

Dimension: scalar

nfft

The size of the fft.

Type: integer

Dimension: scalar

fs

The sampling frequency.

Type: double

Dimension: scalar

range

The spectrum type: 'onesided' or 'twosided'.

Type: string

Outputs

msc

The mean squared coherence.

Type: vector

freq

The vector of frequencies corresponding to the coherence values.

Type: vector

Example

Coherence of two signals sharing common frequency components.

n = 4096;
fs = 256;
ts = 1/fs;
t = [0:ts:(n-1)*ts];
w1 = 2*pi*20;
w2 = 2*pi*32;
w3 = 2*pi*48;
w4 = 2*pi*60;
signal1 = 5*cos(w1*t) + 7*cos(w2*t) + 3*cos(w4*t);
signal2 = 7*cos(w1*t + (pi/2)) + 5*sin(w3*t) + 2*cos(w4*t + pi);
rand('seed', 2019);
signal1 = signal1 + randn(1, n);
signal2 = signal2 + randn(1, n);
window = ones(1, 64);
mscohere(signal1, signal2, window, 0, [], fs);

Figure 1. impz figure 1

Comments

With no return arguments, the function will automatically plot.

The 'onesided' output has a length of nfft/2+1 if nfft is even, or (nfft+1)/2 if nfft is odd.

It is often recommended to remove the signal means prior to calling mscohere. The function does not remove the mean automatically.