p10_3.m

数字信号处理试验指导书(sourcecode)

% Program P10_3
% Effect of Up-sampling in the Frequency Domain
% Use fir2 to create a bandlimited input sequence
freq = [0 0.45 0.5 1];
mag = [0 1 0 0];
x = fir2(99, freq, mag);
% Evaluate and plot the input spectrum
[Xz, w] = freqz(x, 1, 512);
subplot(2,1,1);
plot(w/pi, abs(Xz)); axis([0 1 0 1]); grid
xlabel('\omega/