Apply a digital filter (direct form II transposed): Difference between revisions

=={{header|FreeBASIC}}==

{{trans|Yabasic}}

<lang freebasic>Sub Filtro(a() As Double, b() As Double, senal() As Double, resultado() As Double)

Dim As Integer j, k

Dim As Double tmp

For j = 0 To Ubound(senal)

tmp = 0

For k = 0 To Ubound(b)

If (j-k < 0) Then Continue For

tmp = tmp + b(k) * senal(j-k)

Next k

For k = 0 To Ubound(a)

If (j-k < 0) Then Continue For

tmp = tmp - a(k) * resultado(j-k)

Next k

tmp /= a(0)

resultado(j) = tmp

Next j

End Sub

Dim Shared As Double a(4), b(4), senal(20), resultado(20)

Dim As Integer i

For i = 0 To 3 : Read a(i) : Next i

For i = 0 To 3 : Read b(i) : Next i

For i = 0 To 19 : Read senal(i) : Next i

Filtro(a(),b(),senal(),resultado())

For i = 0 To 19

Print Using "###.########"; resultado(i);

If (i+1) Mod 5 <> 0 Then

Print ", ";

Else

Print

End If

Next i

'' a()

Data 1, -2.77555756e-16, 3.33333333e-01, -1.85037171e-17

'' b()

Data 0.16666667, 0.5, 0.5, 0.16666667

'' senal()

Data -0.917843918645, 0.141984778794, 1.20536903482, 0.190286794412

Data -0.662370894973, -1.00700480494, -0.404707073677, 0.800482325044

Data 0.743500089861, 1.01090520172, 0.741527555207, 0.277841675195

Data 0.400833448236, -0.2085993586, -0.172842103641, -0.134316096293

Data 0.0259303398477, 0.490105989562, 0.549391221511, 0.9047198589

Sleep</lang>

{{out}}

<pre>

-0.15297399, -0.43525783, -0.13604340, 0.69750333, 0.65644469

-0.43548245, -1.08923946, -0.53767655, 0.51704999, 1.05224975

0.96185430, 0.69569009, 0.42435630, 0.19626223, -0.02783512

-0.21172192, -0.17474556, 0.06925840, 0.38544587, 0.65177084

</pre>