moving average formant added

downsample_analysis.m

@@ -2,7 +2,7 @@ clear all
 close all 
 clc
 
-% Modify the desired frequency foir the whole code here
+% Modify the desired frequency for the whole code here
 desired_freq = 4000;
 % Read and Set up coeficient
 [y, fs] = audioread("sound/modulator22.wav");

spectral_analysis.m

@@ -3,32 +3,37 @@ close all
 clc
 
 [y, fs] = audioread("sound/modulator22.wav");
-ranges = [17000, 20000; 29000, 37000; 41000, 46000];
+ranges = [17000, 21000; 30500, 36000; 41500, 46000]; 
 one = y(ranges(1,1):ranges(1,2));
 two = y(ranges(2,1):ranges(2,2));
 three = y(ranges(3,1):ranges(3,2));
 
-word = one;
+word = three;
 
 n = length(word);   
 f = (0:n-1)*(fs/n);
 f1 = 0;%Hz
-f2 = 4000;%Hz
+f2 = 2500;%Hz
 idx = find(f >= f1 & f <= f2); %define the index of the freq range
 f = f(idx);
 y = fft(word, n);% compute DFT of input signal
 power = abs(y).^2/n;
-power = power(idx);
+power = power(idx);%limit the signal to the frequency ROI 
 [val, ind] = max(power);
 
-%lowpass for the formant
+%lowpass for the formant, moving average
-
-Fc = 2000; % define the cutoff frequency of the low-pass filter
-[b, a] = butter(6, Fc/(fs/2), 'low'); % design a 4th-order Butterworth low-pass filter
-Pxx_filt = filter(b, a, power); % apply the filter to the power spectrum
-length(Pxx_filt)
-length(f)
 
+for j = 1:length(idx)
+  tot = 0;
+  for k = j-18:j
+    if k <=0
+      tot = tot + power(1);
+    else
+      tot = tot + power(k);
+    endif
+  endfor
+  power_avg(j) = 1/6*(tot);
+endfor
 
 figure;
 
@@ -39,7 +44,7 @@ ylabel('Amplitude (a.u.)');
 
 subplot(1,2,2) % freq range plot 
 plot(f,10*log10(power/power(ind))); hold on;
-plot(f, 10*log10(Pxx_filt), 'r');
+plot(f, 10*log10(power_avg/power(ind)), 'r');
 xlabel('Frequency (Hz)')
 ylabel('Power (dB)')