Animated Demo for forirrer series

Category:

ASP, HTML and XML

Type:

Snippets

Difficulty:

Beginning

Author: Anonymous

Version Compatibility: Visual Basic 6

More information:

An excellent demonstration of what is misspelled in various places in this example of the Fourier Series/Transform.

Instructions: Copy the declarations and code below and paste directly into your VB project.

Declarations:
' (None)

Code:

VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   5175
   ClientLeft      =   60
   ClientTop       =   450
   ClientWidth     =   11625
   LinkTopic       =   "Form1"
   ScaleHeight     =   5175
   ScaleWidth      =   11625
   StartUpPosition =   3  'Windows Default
   Begin VB.CommandButton Command2 
      Caption         =   "CLEAR PIC BOX"
      Height          =   495
      Left            =   8640
      TabIndex        =   4
      Top             =   0
      Width           =   855
   End
   Begin VB.CommandButton Command1 
      Caption         =   "PLOT"
      Height          =   375
      Left            =   7920
      TabIndex        =   3
      Top             =   120
      Width           =   735
   End
   Begin VB.TextBox Text1 
      Height          =   285
      Left            =   840
      TabIndex        =   1
      Text            =   "1"
      Top             =   120
      Width           =   495
   End
   Begin VB.PictureBox P1 
      Height          =   4215
      Left            =   480
      ScaleHeight     =   4155
      ScaleWidth      =   8955
      TabIndex        =   0
      Top             =   480
      Width           =   9015
      Begin VB.Line Xtick 
         BorderColor     =   &H000000FF&
         Index           =   0
         Visible         =   0   'False
         X1              =   840
         X2              =   840
         Y1              =   2760
         Y2              =   3000
      End
      Begin VB.Line Yaxis 
         X1              =   720
         X2              =   2760
         Y1              =   2280
         Y2              =   2280
      End
      Begin VB.Line Xaxis 
         X1              =   720
         X2              =   2640
         Y1              =   1920
         Y2              =   1920
      End
   End
   Begin VB.Label Label1 
      BackColor       =   &H0080FFFF&
      BorderStyle     =   1  'Fixed Single
      Caption         =   "Demonstrstion of Fourire Series for a GATE or SQUARE wave"
      BeginProperty Font 
         Name            =   "MS Sans Serif"
         Size            =   9.75
         Charset         =   0
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      ForeColor       =   &H000000FF&
      Height          =   375
      Left            =   1440
      TabIndex        =   5
      Top             =   120
      Width           =   6495
   End
   Begin VB.Label lbTerms 
      BackColor       =   &H00FFFFFF&
      Caption         =   "n="
      BeginProperty Font 
         Name            =   "MS Sans Serif"
         Size            =   13.5
         Charset         =   0
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      ForeColor       =   &H00FF0000&
      Height          =   285
      Left            =   480
      TabIndex        =   2
      Top             =   120
      Width           =   495
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Dim PI As Double, RD As Double
Dim a(400) As Double, b(400) As Double
Dim cumA As Double, s(3) As Double

Private Sub Command1_Click()
eval

End Sub

Private Sub Command2_Click()
P1.Cls
End Sub

Private Sub Form_Load()
Me.Show
PI = 4 * Atn(1): RD = PI / 180
s(0) = 0: s(1) = 1: s(2) = 0: s(3) = -1
P1.Scale (-1000, 1.5)-(1000, -1.5)
axes

End Sub

Public Sub axes()
With Xaxis
.Visible = True
.X1 = -1000
.Y1 = 0
.X2 = 1000
.Y2 = 0
End With
With Yaxis
.Visible = True
.X1 = 0
.Y1 = -1.5
.X2 = 0
.Y2 = 1.5
End With
For i = 1 To 20
Load Xtick(i)
With Xtick(i)
.Visible = True
.X1 = -1000 + (i - 1) * 125
.Y1 = 0
.X2 = Xtick(i).X1
.Y2 = -0.1
End With
Next
End Sub

Public Sub eval()
Static coln As Integer
sx = 2 * PI / 500
a0 = 4 / PI
For x = -1000 To 1000 Step 0.01
t = sx * x
n = Text1.Text
cumA = 0
For i = 1 To n
b(i) = 0
j = i Mod 4
a(i) = s(j) * Cos(i * t) / i
If i Mod 2 = 0 Then a(i) = 0
cumA = cumA + a(i)
Next

y = a0 * cumA
colour = coln Mod 15
P1.PSet (x, y), QBColor(colour)
cumA = 0
Next
coln = coln + 1
End Sub