From 802c3166f21c27310e98b7887a77f369838d9c60 Mon Sep 17 00:00:00 2001
From: "adrien.combe" <adrien.combe@ecam.fr>
Date: Thu, 20 Apr 2023 11:16:13 +0200
Subject: [PATCH] Signal process 2

---
 Midterm-Adrien-COMBE-codes/Signal2.m | 45 ++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 Midterm-Adrien-COMBE-codes/Signal2.m

diff --git a/Midterm-Adrien-COMBE-codes/Signal2.m b/Midterm-Adrien-COMBE-codes/Signal2.m
new file mode 100644
index 0000000..97a4b0b
--- /dev/null
+++ b/Midterm-Adrien-COMBE-codes/Signal2.m
@@ -0,0 +1,45 @@
+% Load the signal from the CSV file
+data = csvread('unknownsignal.csv');
+signal = data(:, 1);
+
+% Set the sampling frequency
+Fs = 300; % Hz
+
+% Define the frequency range of interest
+fmin = 30; % Hz
+fmax = 40; % Hz
+
+% Apply a Hanning window to the signal to reduce spectral leakage
+win = hanning(length(signal));
+signal_win = signal .* win;
+
+% Calculate the power spectral density (PSD) of the signal using Welch's method
+nfft = 1024;
+[Pxx, f] = pwelch(signal_win, win, [], nfft, Fs);
+
+% Find the frequency indices that correspond to the frequency range of interest
+idx_min = find(f >= fmin, 1);
+idx_max = find(f <= fmax, 1, 'last');
+
+% Extract the PSD of the signal in the frequency range of interest
+Pxx_interest = Pxx(idx_min:idx_max);
+
+% Find the frequency at which the PSD is maximum in the frequency range of interest
+[~, idx_max_interest] = max(Pxx_interest);
+f_interest = f(idx_min+idx_max_interest-1);
+
+% Plot the PSD of the signal and the frequency range of interest
+figure;
+plot(f, 10*log10(Pxx));
+hold on;
+plot([fmin, fmax], [0, 0], 'r', 'LineWidth', 2);
+xlim([0, Fs/2]);
+ylim([-100, max(10*log10(Pxx))]);
+xlabel('Frequency (Hz)');
+ylabel('Power/Frequency (dB/Hz)');
+title(sprintf('Signal PSD with frequency range of interest [%d %d] Hz', fmin, fmax));
+grid on;
+legend('Signal PSD', 'Frequency range of interest');
+
+% Print the frequency at which the PSD is maximum in the frequency range of interest
+fprintf('The signal of interest is at %.2f Hz\n', f_interest);