Hi maham,
To find the maximum frequency component of an audio signal, you can follow these steps:
- Load the audio file and perform the Fast Fourier Transform (FFT).
- Compute the magnitude spectrum of the FFT.
- Identify the frequency corresponding to the maximum magnitude in the spectrum.
- Plot the magnitude spectrum and highlight the maximum frequency component.
Please refer to the following code snippet:
% Load the audio file
% 'audioread' reads the audio file 'filename.wav' and returns the audio data 'y' and the sampling frequency 'Fs'
[y, Fs] = audioread('filename.wav');
% Perform FFT
% 'fft' computes the Fast Fourier Transform of the audio signal 'y'
xfft = fft(y);
% Compute the magnitude spectrum
% 'abs' computes the magnitude of the complex FFT result to get the magnitude spectrum
magnitude_spectrum = abs(xfft);
% Create a frequency vector
% The length of the signal 'y' is stored in 'N'
N = length(y);
% The frequency vector is created, ranging from 0 to Fs-1, with N points
frequencies = (0:N-1)*(Fs/N);
% Find the index of the maximum magnitude
% 'max' finds the maximum value in the magnitude spectrum and its corresponding index
[max_magnitude, max_index] = max(magnitude_spectrum);
% Find the corresponding frequency
% The frequency corresponding to the maximum magnitude is found using the index 'max_index'
max_frequency = frequencies(max_index);
% Plot the magnitude spectrum
% 'figure' creates a new figure window
figure;
% 'plot' plots the magnitude spectrum against the frequency vector
plot(frequencies, magnitude_spectrum);
% 'xlabel' labels the x-axis
xlabel('Frequency (Hz)');
% 'ylabel' labels the y-axis
ylabel('Magnitude');
% 'title' adds a title to the plot
title('Magnitude Spectrum');
% 'grid on' adds a grid to the plot for better readability
grid on;
% Highlight the maximum frequency component
% 'hold on' allows adding more plots to the existing figure
hold on;
% 'plot' highlights the maximum frequency component with a red circle ('ro')
plot(max_frequency, max_magnitude, 'ro');
% 'text' adds a text annotation to the plot at the location of the maximum frequency component
text(max_frequency, max_magnitude, sprintf('Max Frequency: %.2f Hz', max_frequency), 'VerticalAlignment', 'bottom', 'HorizontalAlignment', 'right');
% 'hold off' releases the hold on the current figure
hold off;
% Display the maximum frequency
% 'disp' displays the maximum frequency component in the command window
disp(['The maximum frequency component is: ', num2str(max_frequency), ' Hz']);
I hope this helps!
