X-Git-Url: https://adrianiainlam.tk/git/?p=4yp.git;a=blobdiff_plain;f=CDCompensation.m;h=9f01950d79fe1c90a62c19c4938002580db9b954;hp=1f3cc2c641e2b156e0213f38a03cb36f637c92fa;hb=5fae00773184080617ac022c07495d365975e0e1;hpb=427465905320390cebf3d247b8beace19387c70f

diff --git a/CDCompensation.m b/CDCompensation.m
index 1f3cc2c..9f01950 100644
--- a/CDCompensation.m
+++ b/CDCompensation.m
@@ -21,11 +21,20 @@ function [yCDComp, kstart] = CDCompensation(y, D, lambda, z, Tsamp)
   kstart = -floor(N/2);
 
   % h: FIR filter
-  h = sqrt(j * c * Tsamp^2 / (D * lambda^2 * z)) * ...
-      exp(-j * pi * c * Tsamp^2 * k .^ 2 / (D * lambda^2 * z));
+  h = exp(-j * pi * c * Tsamp^2 * k .^ 2 / (D * lambda^2 * z));
+
+  len_fft = max(length(y), length(h));
+  H = fft(h, len_fft);
+  Y = fft(y, len_fft);
+
+  yCDComp = ifft(H.' .* Y);
+  l = (length(h) - 1) / 2;
+  if l > 0
+    yCDComp = [yCDComp(l:end); yCDComp(1:l-1)];
+  else
+    yCDComp = [yCDComp(end); yCDComp(1:end-1)];
+  end
 
-  yCDComp = upfirdn(y, h);
-  yCDComp = yCDComp(N:end); % truncate filter transients
 end
 %% References
 %% [1]: S.J. Savory, Digital filters for coherent optical receivers, 2008.