Improved speed and clarity of code for the winSincFracDel.m and update date

Signal Processing/Generic/MATLAB/Functions/winSincFracDel.m

@@ -3,7 +3,7 @@
 % Author: Achilles Kappis
 % e-mail: axilleaz@protonmail.com
 %
-% Date: 17/04/2024 (DD/MM/YYYY)
+% Date: 13/08/2024 (DD/MM/YYYY)
 %
 % Copyright: MIT
 % --------------------------------------------------
@@ -133,43 +133,43 @@ function [sincFilt, causDel, dSig] = winSincFracDel(del, len, winFun, sig, sigLe
         sigLen = "Full";
     end
 
+    
+    % ====================================================
+    % Calculate some parameters
+    % ====================================================
+    fracDel = del - abs(rem(intDel, 1)); % Fractional part of the delay
+
+    
     % ====================================================
     % Generate FIR filter for fractional delay
     % ====================================================
-    idx = (-len + 1:len).'; % Filter sample indices
+    idx = floor(-len/2 + 1):floor(len/2); % Filter sample indices
     
-    causDel = -floor(idx(1)/2); % The causal delay of the filter
-    sincFilt = sinc(idx - del); % Calculate the filter
+    causDel = -idx(1); % The causal delay of the filter
+    sincFilt = sinc(idx - fracDel); % Calculate the filter
 
 
     % ====================================================
     % Apply windowing
     % ====================================================
-    fracDel = abs(rem(del, 1)); % Total filter delay
-
     % Generate window
     if isstring(winFun)
         switch lower(winFun)
+            case "rectangular"
+                win = ones(length(idx), 1);
             case "hann"
-                win = sin(pi * (idx - fracDel)/len).^2;
+                win = sin(pi * (idx - fracDel + causDel + 1)/len).^2;
             case "hamming"
                 alpha = 25/46;
-                win = alpha - (1 - alpha) * cos(2 * pi * (idx - fracDel)/len);
-            otherwise % Rectangular
-                win = ones(length(idx), 1);
+                win = alpha - (1 - alpha) * cos(2 * pi * (idx - fracDel + causDel + 1)/len);    
         end
     else
         % Kaiser window
-        win = besseli(0, pi * winFun * sqrt(1 - (2 * (idx - del)/len).^2))/besseli(0, pi * winFun);
+        win = besseli(0, pi * winFun * sqrt(1 - (2 * (idx - fracDel)/len).^2))/besseli(0, pi * winFun);
     end
     
-    % Shift window function to centre on sinc's peak
-    if ~isscalar(winFun)
-        win = delayseq(win, floor(del) + causDel);
-    end
-
-    % Apply window function and keep only the causal part up to the length of the filter
-    sincFilt = sincFilt(causDel + 1:causDel + len) .* win(causDel + 1:causDel + len);
+    % Apply window to the filter
+    sincFilt = sincFilt .* win;
 
 
     % ====================================================