sinusoid.m

matlab 源程序

%an example to generate a sinusoid signal
clear;

%magnitude is A
A = 5;

%f_sig is the frequency of the signal, T_sig is the corresponding period
f_sig = 3; T_sig = 1/f_sig;

%T_max is the maximum number of time
T_max = 2*T_sig;

%Ts is the sampling interval of the continuous time signal (Fs is sampling
%rate)
Ts = 1e-3;  Fs = 1/Ts;

%generate time vector
t = -T_max:Ts:T_max;

%a complicated way to generate the signal vector by setting the values of
%the vector element by element
t_len = length(t);
mid_point = (t_len+1)/2;
for i = 1:t_len
    t_now = (i-mid_point)*Ts;
    cos_t(i) = A*cos(2*pi*f_sig*t_now);
end

%a much easier way to generate the signal vector by setting the vector
%directly.
vector_sig = A*sin(2*pi*f_sig*t);

%plot the signal
plot(t, cos_t);
hold on;    grid on;
plot(t, vector_sig,'r');
ylabel('x(t)');
xlabel('t (sec)');
ylim([-A*1.1, A*1.1]);