From 9ac9c6f724c16a172ecb923a0360bc9a9ffc3806 Mon Sep 17 00:00:00 2001
From: wukong <wukong@longaeva>
Date: Tue, 25 Dec 2018 14:44:46 -0800
Subject: began merging windowing scripts; swapped std_dev and std_err in mean
 and mean_avg;

---
 hamming.awk | 48 +++++++++++++++++++++++++++++++++---------------
 1 file changed, 33 insertions(+), 15 deletions(-)

(limited to 'hamming.awk')

diff --git a/hamming.awk b/hamming.awk
index f7ff9f7..acfde97 100644
--- a/hamming.awk
+++ b/hamming.awk
@@ -2,35 +2,52 @@
 
 ### hamming.awk
 # generate a Hamming window
+# 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.
 
-BEGIN {
 
-    ARGV[1] ? N = ARGV[1] : N = 0
-    ARGV[2] ? OFMT = "%." ARGV[2] "g" : OFMT = "%g"
+### Gaussian
+function gaussian(n) {
+    # sigma <= 0.5
+    sigma = 0.4
+    e[n] = (n)/(sigma*M)
+    return exp(-0.5*e[n]*e[n])
+}
 
-    # window interval goes from -M to M
-    M = 0.5*(N - 1)
-    pi = 4*atan2(1,1)
 
-    ### R.W. Hamming, "Digital Filters"
-    # H = "0.23 0.54 0.23"
+### Hamming, raised cosine
+function hamming(n) {
+    ### optimal values for equal-ripple
+    #a0 = 0.53836
+    #a1 = 0.46164
 
     a0 = (25.0/46.0)
     a1 = (21.0/46.0)
+    return a0 + a1*cos((pi*n)/M)
+}
 
-    ### optimal values for equal-ripple
-    #a0 = 0.53836
-    #a1 = 0.46164
 
-    ### VonHann
-    #a0 = 0.5
-    #a1 = 0.5
+### vonHann, raised cosine
+function vonhann(n) {
+    a0 = 0.5
+    a1 = 0.5
+    return a0 + a1*cos((pi*n)/M)
+}
+
+
+BEGIN {
+
+    ARGV[1] ? N = ARGV[1] : N = 0
+    ARGV[2] ? OFMT = "%." ARGV[2] "g" : OFMT = "%g"
+
+    # window interval goes from -M to M
+    M = 0.5*(N - 1)
+    pi = 4*atan2(1,1)
 
     for (n=-M; n<=M; n++) {
         if (N > 1 && M > 0) {
-            w[n] = a0 + a1*cos((pi*n)/M)
+            w[n] = hamming(n)
             print n + M, w[n]/M
         }
         else {
@@ -39,3 +56,4 @@ BEGIN {
     }
 
 }
+
-- 
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