apd sapt 7 assig1

% Define filter specifications
Fp = 500;   % Cutoff frequency in Hz
Fst = 600;  % Stopband frequency in Hz
Fs = 2000;  % Sample frequency in Hz
Rp = 3;     % Maximum passband ripple in dB
A = 40;     % Stopband attenuation in dB

% Normalize frequencies
Wp = 2 * Fp / Fs;   % Cutoff frequency in radians/sample
Wst = 2 * Fst / Fs;  % Stopband frequency in radians/sample

% Design the filter using fir1 function
N = fir1(10, Wp, 'low', kaiser(11, 0.5));

% Load an example audio file (replace 'input_audio.wav' with your input audio file)
[input_signal, Fs] = audioread('input_audio.wav');

% Apply the filter to the input signal
output_signal = filter(N, 1, input_signal);

% Plot input and output signals in the time domain
figure;
subplot(2,1,1);
t = 0:1/Fs:(length(input_signal)-1)/Fs;
plot(t, input_signal);
xlabel('Time (s)');
ylabel('Amplitude');
title('Input Signal');

subplot(2,1,2);
plot(t, output_signal);
xlabel('Time (s)');
ylabel('Amplitude');
title('Output Signal');

% Compute and plot magnitude frequency responses
figure;
subplot(2,1,1);
freqz(N, 1, 'half', 1024, Fs);
title('Filter Frequency Response');
xlabel('Frequency (Hz)');
ylabel('Magnitude (dB)');

subplot(2,1,2);
[freq, input_spectrum] = periodogram(input_signal, [], [], Fs);
[freq, output_spectrum] = periodogram(output_signal, [], [], Fs);
plot(freq, 10*log10(input_spectrum), 'b', 'LineWidth', 1.5);
hold on;
plot(freq, 10*log10(output_spectrum), 'r', 'LineWidth', 1.5);
hold off;
xlabel('Frequency (Hz)');
ylabel('Magnitude (dB)');
legend('Input Spectrum', 'Output Spectrum');
title('Input and Output Frequency Responses');