www.gusucode.com > signal 案例源码程序 matlab代码 > signal/HarmonicPowersAndCorrespondingFrequenciesExample.m

    %% Harmonic Powers and Corresponding Frequencies
% Create a signal sampled at 10 kHz. The signal consists of a 100 Hz
% fundamental with amplitude 2 and three odd-numbered harmonics at 300,
% 500, and 700 Hz with amplitudes 0.01, 0.005, and 0.0025. Specify the
% number of harmonics to 7. Determine the THD, the power at the harmonics,
% and the corresponding frequencies.

% Copyright 2015 The MathWorks, Inc.


fs = 10000;
t = 0:1/fs:1-1/fs;
x = 2*cos(2*pi*100*t)+0.01*cos(2*pi*300*t)+ ...
    0.005*cos(2*pi*500*t)+0.0025*sin(2*pi*700*t);
[r,harmpow,harmfreq] = thd(x,10000,7);
[harmfreq harmpow]

%%
% The powers at the even-numbered harmonics are on the order of $-300$ dB,
% which corresponds to an amplitude of $10^{-15}$.