1 files changed, 4 insertions, 1 deletions
diff --git a/fir_window_hamming.awk b/fir_window_hamming.awk
index 5660754..51eb0d8 100644
--- a/fir_window_hamming.awk
+++ b/fir_window_hamming.awk
@@ -5,6 +5,9 @@
 # R.W. Hamming, 'Digital Filters': H = '0.23 0.54 0.23'
 # https://en.wikipedia.org/wiki/Window_function provides a few values for the
 # 'a0' and 'a1' parameters of the raised cosine.
+# note: the forms provided from wikipedia do not give expected results and
+# appear to show inconsistency between raised cosine variations. need to
+# cross-check these forms against DSP/signaling texts.
 
 
 # Hamming window (raised cosine)
@@ -26,7 +29,7 @@ BEGIN {
 
     # window interval goes from -M to M
     M = 0.5*(N - 1)
-    pi = 4*atan2(1,1)
+    pi = 4.0*atan2(1.0,1.0)
 
     for (n=-M; n<=M; n++) {
         if (N > 1 && M > 0) {