% Sampling frequency is 11025 Hz
% Create a signal with two sinusoidal components
% Compute frequency spectrum using DFT/FFT at
% different frequency resolutions.
Fs = 11025;  % Sampling frequency
x = [0:0.01:512];
sinx = sin(x*6*pi);  % 330.75 Hz
sin3x = sin(3*x*6*pi);  % 992.25 Hz
combined = 0.5*(sinx + sin3x);
wavplay (combined, Fs);
t = [0:127]/11025;  % time index for the first 128 samples
plot (t,combined(1:128));  % Plot the signal
xlabel('Time (seconds)');
ylabel('Signal Amplitude');
title('Plot of 2-component signal');
pause;
figure;
N = 32;
f = (0:N-1)/N*Fs;  % Compute frequency scale for N = 32
plot (f,abs(fft(combined(1:32))));  % Plot frequency spectrum for N = 32
xlabel('Frequency (Hz)');
ylabel('FFT Magnitude');
title('Plot of FFT, N = 32');
pause;
figure;
N = 128;
f=(0:N-1)/N*Fs;  % Compute frequency scale for N = 128
plot (f,abs(fft(combined(1:128))));  % Plot frequency spectrum for N = 128
xlabel('Frequency (Hz)');
ylabel('FFT Magnitude');
title('Plot of FFT, N = 128');
pause;
figure;
N = 512;
f=(0:N-1)/N*Fs;  % Compute frequency scale for N = 512
plot (f,abs(fft(combined(1:512))));  % Plot frequency spectrum for N = 512
xlabel('Frequency (Hz)');
ylabel('FFT Magnitude');
title('Plot of FFT, N = 512');