Question

a) Design a Mat lab programme that can be used to modify the signal (signal compression/expansion/scaling etc). Choose your method of modifying of the signal and write appropriate scripts in mat lab. Also after modifying the signal adopt a frequency transform method and transform the signal and plot the magnitude and phase spectrum of the signal

Answer 1

To design a MATLAB program that can modify a signal, you can write a script that applies a specific modification technique such as compression, expansion, or scaling. After modifying the signal, adopt a frequency transform method like the Fourier Transform using the fft() function in MATLAB to plot the magnitude and phase spectrum.

Step-by-step explanation:

To design a MATLAB program that can modify a signal, you can start by writing a script that reads in an audio file and applies a specific modification technique such as signal compression, expansion, or scaling. Here's an example of a script that applies signal compression:

filename = 'audio.wav';
signal = audioread(filename);
compressed_signal = signal / 2;
audiowrite('compressed_audio.wav', compressed_signal, 44100);

After modifying the signal, you can adopt a frequency transform method like the Fourier Transform using the fft() function in MATLAB. Here's an example of how to plot the magnitude and phase spectrum of the modified signal:

transformed_signal = fft(compressed_signal);
magnitude_spectrum = abs(transformed_signal);
phase_spectrum = angle(transformed_signal);
frequency_axis = linspace(0, 44100, length(magnitude_spectrum));

subplot(2, 1, 1);
plot(frequency_axis, magnitude_spectrum);
xlabel('Frequency (Hz)');
ylabel('Magnitude');
subplot(2, 1, 2);
plot(frequency_axis, phase_spectrum);
xlabel('Frequency (Hz)');
ylabel('Phase');

This script will create a two-panel plot with the magnitude spectrum on top and the phase spectrum on the bottom.