form1.frm

DTMF信号产生原程序

VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   6045
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   6510
   LinkTopic       =   "Form1"
   ScaleHeight     =   6045
   ScaleWidth      =   6510
   StartUpPosition =   3  'Windows Default
   Begin VB.ListBox List2 
      Height          =   4935
      Left            =   3480
      TabIndex        =   4
      Top             =   840
      Width           =   2775
   End
   Begin VB.ListBox List1 
      Height          =   4935
      Left            =   360
      TabIndex        =   3
      Top             =   960
      Width           =   2895
   End
   Begin VB.CommandButton Command1 
      Caption         =   "计算"
      Height          =   375
      Left            =   3840
      TabIndex        =   2
      Top             =   120
      Width           =   1455
   End
   Begin VB.TextBox Text1 
      Height          =   375
      Left            =   1320
      TabIndex        =   0
      Top             =   120
      Width           =   2295
   End
   Begin VB.Label Label1 
      Caption         =   "FRQ"
      Height          =   255
      Left            =   360
      TabIndex        =   1
      Top             =   120
      Width           =   855
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Private Sub Command1_Click()
    Dim y1 As Double
    Dim y2 As Double
    Dim temp As Double
    
    Dim y  As Double
    
    Dim frq As Double
    Dim i As Double
    Dim resultstr As String
    List1.Clear
    
    
    y1 = 0
    temp = -905
    y2 = temp
    
    temp = 15333
    i = 0
    While (i < 500)
       y = 2 * temp * y1 / 32768 - y2
      
       y2 = y1
       y1 = y
       resultstr = Str(i) & "      " & Str(CLng(y1))
       List1.AddItem (resultstr)
       
       i = i + 1
    Wend
    
    frq = Int(Text1.Text)
    y1 = 0
    y2 = -Sin(2 * 3.1415926 * frq / 8000)
    
    i = 0
    While (i < 500)
        y = 2 * Cos(2 * 3.1415926 * frq / 8000) * y1 - y2
        
        y2 = y1
        y1 = y
        resultstr = Str(i) & "      " & Str(CLng(y1 * 1024)) 'q值为10
        List2.AddItem (resultstr)
        
        i = i + 1
    Wend
    
    
    
    
End Sub