how to add harmonics to a sine wave ?

57 次查看（过去 30 天）
yuvi
yuvi 2011-5-17
评论： Pham Duy Phuoc 2015-10-27
hi to all
i want to add to a sine wave (220volt and 50hz ) harmonics and to see them in a spectrum ( 50hz , 150hz ,250hz ....)
any suggestions ?
thanks
  1 个评论
Pham Duy Phuoc
Pham Duy Phuoc 2015-10-27
function y = harmonic(x,k)
% assumes that x is a column vector
assert(size(x,1) > 0);
assert(size(x,2) == 1);
% Interpolate by k and add k-th harmonic:
y = interp(x,k) + repmat(x,k,1);
end

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Arturo Moncada-Torres
Mmm, actually is very easy. Just add them to the original signal:
% Sampling
fs = 1000; % Sampling rate [Hz]
Ts = 1/fs; % Sampling period [s]
fNy = fs / 2; % Nyquist frequency [Hz]
duration = 10; % Duration [s]
t = 0 : Ts : duration-Ts; % Time vector
noSamples = length(t); % Number of samples
% Original signal
x = 220.*sin(2 .* pi .* 50 .* t);
% Harmonics
x1 = 100.*sin(2 .* pi .* 100 .* t);
x2 = 100.*sin(2 .* pi .* 200 .* t);
x3 = 100.*sin(2 .* pi .* 300 .* t);
% Contaminated signal
xn = x + x1 + x2 + x3;
% Frequency analysis
f = 0 : fs/noSamples : fs - fs/noSamples; % Frequency vector
% FFT
x_fft = abs(fft(x));
xn_fft = abs(fft(xn));
% Plot
figure(1);
subplot(2,2,1);
plot(t, x);
subplot(2,2,2);
plot(t, xn);
subplot(2,2,3);
plot(f,x_fft);
xlim([0 fNy]);
subplot(2,2,4);
plot(f,xn_fft);
xlim([0 fNy]);
Just some quick code. I tested it and it works.
Hope it helps ;-) . Keep coding!
  2 个评论
Arturo Moncada-Torres
Arturo Moncada-Torres 2011-5-17
Notice how the harmonics have an amplitude of 100 in order to be visualized in the spectrum plot. Otherwise, the original signal's magnitude (220) would be too big compared to the harmonics one.

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Spectral Measurements 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by