added convolution function

src/Daniel_Doan_convolution.m

@@ -0,0 +1,17 @@
+function x = Daniel_Doan_convolution(f,h)
+    %input: two 1d arrays representing two sound signals in the time domain
+    %output: the convolution of the two waves, which is the inverse FT of
+    %FT(f)*FT(h)
+    %author: Daniel Doan
+
+    %padding to ensure the entire convolution is calculated
+    pad = length(f) + length(h) - 1;
+    %take FT of f
+    F = fft(f, pad);
+    %take FT of h
+    H = fft(h, pad);
+    %multiply the two FTs
+    X = F .* H;
+    %take inverse FT of the product
+    x = ifft(X);
+end