fir_window_gaussian.awk


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39

#!/usr/bin/awk -f

### fir_window_gaussian.awk
# generate a Gaussian FIR window
# https://en.wikipedia.org/wiki/Window_function


# Gaussian window
function gaussian(n) {
    # sigma <= 0.5
    sigma = 0.4
    en[n] = (n - M)/(sigma*M)
    return exp(-0.5*e[n]*e[n])
}


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 = 4.0*atan2(1.0, 1.0)

    for (n=0; n<N; n++) {
        if (N > 1 && M > 0) {
            # sigma <= 0.5
            sigma = 0.4
            e[n] = (n - M)/(sigma*M)
            w[n] = exp(-0.5*e[n]*e[n])
            print n, w[n]/M
        }
        else {
            print n, 1.0
        }
    }
}