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

    %% Waveform Generation: Time Vectors and Sinusoids
% Most toolbox functions require you to begin with a vector representing a
% time base. Consider generating data with a 1000 Hz sample frequency, for
% example. An appropriate time vector is

% Copyright 2015 The MathWorks, Inc.


%%
t = (0:0.001:1)';

%%
% where the MATLAB(R) colon operator (|:|) creates a 1001-element row
% vector that represents time running from 0 to 1 seconds in steps of 1 ms.
% The transpose operator (|'|) changes the row vector into a column; the
% semicolon (|;|) tells MATLAB to compute, but not display, the result.

%%
% Given |t|, you can create a sample signal y consisting of two sinusoids,
% one at 50 Hz and one at 120 Hz with twice the amplitude.

y = sin(2*pi*50*t) + 2*sin(2*pi*120*t);

%%
% The new variable |y|, formed from vector |t|, is also 1001 elements long.
% You can add normally distributed white noise to the signal and plot the
% first 50 points:

yn = y + 0.5*randn(size(t));
plot(t(1:50),yn(1:50))