%MATLAB PROGRAM 7-1
%create a signal and save as MAT-file
randn('state',0);
N=4000;
Fs=1000;
n=0:N-1;
t=n/Fs;
x=sin(2*pi*50*t)+sin(2*pi*200*t)+randn(1,N);
plot(t,x)
grid
save hdata.mat x Fs