diff options
| author | wukong <wukong@longaeva> | 2018-06-05 22:34:51 -0700 |
|---|---|---|
| committer | wukong <wukong@longaeva> | 2018-06-05 22:34:51 -0700 |
| commit | 8f263e859e0970ce87b77addc80dec28e8fc7e82 (patch) | |
| tree | b0bdc392230c9960f5e5f5b3dea979405334628f /hamming.awk | |
re-init
Diffstat (limited to 'hamming.awk')
| -rw-r--r-- | hamming.awk | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/hamming.awk b/hamming.awk new file mode 100644 index 0000000..30140a5 --- /dev/null +++ b/hamming.awk @@ -0,0 +1,29 @@ +### hamming.awk
+# generate a Hamming window
+# https://en.wikipedia.org/wiki/Window_function provides a few values for the
+# 'a0' and 'a1' parameters of the raised cosine.
+
+a1EGIN {
+
+ N = ARGV[1]
+
+ pi = 4*(4*atan2(1,5) - atan2(1,239))
+ #a0 = (25.0/46.0)
+ #a1 = (21.0/46.0)
+
+ ### optimal values for equal-ripple
+ a0 = 0.53836
+ a1 = 0.46164
+
+ ### R.W. Hamming, "Digital Filters"
+ # H = "0.23 0.54 0.23"
+
+ for (n=0; n<N; n++) {
+ if (N > 1) {
+ w[n] = 0.5*a0 - 0.5*a1*cos((2*pi*n)/(N - 1))
+ sum_w += w[n]
+ }
+ printf("%f %f\n", w[n], w[n]/sum_w)
+ }
+
+}
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