Tiefpassfilter - VB.Net Beispiel

Public Class frmHochPass

Dim pixelx, pixely
Dim pixelxb, pixelyb
Dim vt, vtb

Dim ugrund, uv

Dim P1 As Point
Dim pz As Point
Dim P2 As Point

Dim P1b As Point
Dim pzb As Point
Dim P2b As Point
Dim stiftl As New Pen(Color.LightGreen, 1)

Private Sub pSet(ByVal x As Integer, ByVal y As Integer)
P1.X = x
P1.Y = y
pz.X = 1
pz.Y = 1

Dim vsize As New Size(pz)
Dim rect As New Rectangle(P1, vsize)
PictureBox1.CreateGraphics.DrawRectangle(Pens.LightGreen, rect) ‘, P1) ‘, P1)
End Sub

Private Sub Line(ByVal x As Integer, ByVal y As Integer)
P2.X = x
P2.Y = y

PictureBox1.CreateGraphics.DrawLine(stiftl, P1, P2)
P1.X = x
P1.Y = y
End Sub

Private Sub pSet2(ByVal x As Integer, ByVal y As Integer)
P1b.X = x
P1b.Y = y
pzb.X = 1
pzb.Y = 1

Dim vsize As New Size(pz)
Dim rect As New Rectangle(P1b, vsize)
PictureBox1.CreateGraphics.DrawRectangle(Pens.LightGreen, rect) ‘, P1) ‘, P1)
End Sub

Private Sub Line2(ByVal x As Integer, ByVal y As Integer)
P2b.X = x
P2b.Y = y

PictureBox1.CreateGraphics.DrawLine(stiftl, P1b, P2b)
P1b.X = x
P1b.Y = y
End Sub

Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Dim freq, u0, uC, r, Xc, phasev, f, z
Dim c As Double

freq = (VScrollBarF.Maximum + VScrollBarF.Minimum - VScrollBarF.Value) / 10
u0 = 2
ZeichnenSinb(freq, 3, u0, 0.5, 0) ‘Eingangsspannung zeichnen
‘Widerstand R
r = ((VScrollBarR.Maximum + VScrollBarR.Minimum) - VScrollBarR.Value) * 1000
c = ((VScrollBarC.Maximum + VScrollBarC.Minimum) - VScrollBarC.Value) * (10 ^ -8)
f = freq * 1000
‘Widerstand Rc
Xc = 1 / (f * 2 * Math.PI * c)
‘Ur berechnen
z = Math.Sqrt(r * r + Xc * Xc)
uC = (u0 * Xc) / z
‘Phasenverschiebung berechnen
phasev = (-Math.Acos(uC / u0)) * 180 / Math.PI
‘Ur Zeichen
ZeichnenSin(freq, 3, uC, 0.5, phasev)
End Sub

Private Sub ZeichnenSin(ByVal f As Double, ByVal u0 As Integer, ByVal umax As Double, ByVal dime As Double,ByVal phase As Double)
Dim xvt, i, ut
‘Gitter zeichnen
If pixelx = 0 Then

For i = 0 To 14
For j = 0 To 11
pSet(5 + (i * 10), (j * 10) + 5)
Next j
Next i
pSet(0, pixely)
End If
‘X Koordinaten +1, mit Reset
pixelx = pixelx + 2
If pixelx >= 150 Then
PictureBox1.Image = Nothing
pixelx = 0
End If
‘Zeit des Sinus
‘Herzangabe Frequenz bei Timer = 20ms
vt = vt + (7.2 * f)
If vt >= 361 Then vt = 0
xvt = Math.PI * ((vt + phase) / 180.0)
‘Ut kurz vor Ausgabe. UV muss berechnet werden
ut = u0 + (Math.Sin(xvt)) * umax

pixely = 115 - ut * (10 / dime)  ‘*20 denn 1v = 2 Kästchen
If pixely > 115 Then pixely = 115
If pixely < 5 Then pixely = 5
Line(pixelx, pixely)
End Sub

Private Sub ZeichnenSinb(ByVal f As Double, ByVal u0 As Integer, ByVal umax As Double, ByVal dime As Double,ByVal phase As Double)
Dim xvtb, ut
‘X Koordinaten  +2
pixelxb = pixelxb + 2
If pixelxb >= 150 Then
PictureBox1.Image = Nothing
pixelxb = 0
End If

‘Herzangabe Frequenz bei Timer = 20ms
vtb = vtb + (7.2 * f)
If vtb >= 361 Then vtb = 0
xvtb = Math.PI * ((vtb + phase) / 180.0)
ut = u0 + (Math.Sin(xvtb)) * umax

pixelyb = 115 - ut * (10 / dime)  ‘*20 denn 1v = 2 Kästchen
If pixelyb > 115 Then pixelyb = 115
If pixelyb < 5 Then pixelyb = 5
Line2(pixelxb, pixelyb)

End Sub

Private Sub VScrollBarF_Scroll(ByVal sender As System.Object, ByVal e AsSystem.Windows.Forms.ScrollEventArgs) Handles VScrollBarF.Scroll
lbF.Text = “f = " + Str((VScrollBarF.Maximum + VScrollBarF.Minimum - VScrollBarF.Value) / 10) + " kHz”
End Sub

Private Sub VScrollBarC_Scroll(ByVal sender As System.Object, ByVal e AsSystem.Windows.Forms.ScrollEventArgs) Handles VScrollBarC.Scroll
lbC.Text = “C = " + Str((VScrollBarC.Maximum + VScrollBarC.Minimum - VScrollBarC.Value) / 100) + " µF    “
End Sub

Private Sub VScrollBarR_Scroll(ByVal sender As System.Object, ByVal e AsSystem.Windows.Forms.ScrollEventArgs) Handles VScrollBarR.Scroll
lbR.Text = “R = " + Str(VScrollBarR.Maximum + VScrollBarR.Minimum - VScrollBarR.Value) + " kOhm”
End Sub

Private Sub frmHochPass_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) HandlesMyBase.Load

End Sub
End Class