Apply a digital filter (direct form II transposed): Difference between revisions
Apply a digital filter (direct form II transposed) (view source)
Revision as of 12:13, 27 May 2022
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Line 1,720:
0.96185430, 0.69569009, 0.42435630, 0.19626223, -0.02783512
-0.21172192, -0.17474556, 0.06925841, 0.38544587, 0.65177084</pre>
=={{header|Vlang}}==
{{trans|Go}}
<lang vlang>struct Filter {
b []f64
a []f64
}
fn (f Filter) filter(inp []f64) []f64 {
mut out := []f64{len: inp.len}
s := 1.0 / f.a[0]
for i in 0..inp.len {
mut tmp := 0.0
mut b := f.b
if i+1 < b.len {
b = b[..i+1]
}
for j, bj in b {
tmp += bj * inp[i-j]
}
mut a := f.a[1..]
if i < a.len {
a = a[..i]
}
for j, aj in a {
tmp -= aj * out[i-j-1]
}
out[i] = tmp * s
}
return out
}
//Constants for a Butterworth Filter (order 3, low pass)
const bwf = Filter{
a: [f64(1.00000000), -2.77555756e-16, 3.33333333e-01, -1.85037171e-17],
b: [f64(0.16666667), 0.5, 0.5, 0.16666667],
}
const sig = [
f64(-0.917843918645), 0.141984778794, 1.20536903482, 0.190286794412,
-0.662370894973, -1.00700480494, -0.404707073677, 0.800482325044,
0.743500089861, 1.01090520172, 0.741527555207, 0.277841675195,
0.400833448236, -0.2085993586, -0.172842103641, -0.134316096293,
0.0259303398477, 0.490105989562, 0.549391221511, 0.9047198589,
]
fn main() {
for v in bwf.filter(sig) {
println("${v:9.6}")
}
}</lang>
{{out}}
<pre>
-0.152974
-0.435258
-0.136043
0.697503
0.656445
-0.435482
-1.089239
-0.537677
0.517050
1.052250
0.961854
0.695690
0.424356
0.196262
-0.027835
-0.211722
-0.174746
0.069258
0.385446
0.651771
</pre>
=={{header|Wren}}==
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