VB6.0编程   实现对采集的数据做FFT快速傅里叶变换  也就是 蝶形算法 只要代码就行。 在网上看了几个  大部分都对 但是不知道哪里还有错。https://www.    网上看到的。

有会的 或者知道代码的 麻烦告知下 有偿 谢谢啦

你好 不是单独的用VB做FFT   而是用数据采集卡采集数据  对采集的数据做FFT蝶形运算 得到频率  下面是代码   求到的频率和实际值不符合 而且五秒左右变换一次频率   正常希望的是一秒做一次FFT 显示一次频率

Option Explicit
  
'*模块********************************************************
'FFT0 数组下标以0开始
'AR() 数据实部         AI() 数据虚部
'N 数据点数，为2的整数次幂
'NI 变换方向 1为正变换，-1为反变换
'***************************************************************
Public Jieguo() As Double
      
Const pi = 3.1415926
Public Function FFT0(AR() As Double, AI() As Double, n As Long, ni As Double)
    Dim i As Long, j As Long, k As Long, L As Long, m As Long
    Dim IP As Double, LE As Double
    Dim L1 As Double, N1 As Double, N2 As Double
    Dim SN As Double, TR As Double, TI As Double, WR As Double, WI As Double
    Dim UR As Double, UI As Double, US As Double
    m = NTOM(n)
    N2 = n / 2
    N1 = n - 1
    SN = ni
    j = 1
    For i = 1 To N1
        If i < j Then
            TR = AR(j - 1)
            AR(j - 1) = AR(i - 1)
            AR(i - 1) = TR
            TI = AI(j - 1)
            AI(j - 1) = AI(i - 1)
            AI(i - 1) = TI
        End If
        k = N2
        While (k < j)
            j = j - k
            k = k / 2
        Wend
        j = j + k
    Next i
    For L = 1 To m
        LE = 2 ^ L
        L1 = LE / 2
        UR = 1#
        UI = 0#
        WR = Cos(pi / L1)
        WI = SN * Sin(pi / L1)
        For j = 1 To L1
            For i = j To n Step LE
                IP = i + L1
                TR = AR(IP - 1) * UR - AI(IP - 1) * UI
                TI = AI(IP - 1) * UR + AR(IP - 1) * UI
                AR(IP - 1) = AR(i - 1) - TR
                AI(IP - 1) = AI(i - 1) - TI
                AR(i - 1) = AR(i - 1) + TR
                AI(i - 1) = AI(i - 1) + TI
            Next i
            US = UR
            UR = US * WR - UI * WI
            UI = UI * WR + US * WI
        Next j
    Next L
    If SN <> -1 Then
        For i = 1 To n
            AR(i - 1) = AR(i - 1) / n
            AI(i - 1) = AI(i - 1) / n
        Next i
    End If
End Function
  
Private Function NTOM(n As Long) As Long
    Dim ND As Single
    ND = n
    NTOM = 0
    While (ND > 1)
        ND = ND / 2
        NTOM = NTOM + 1
    Wend
End Function

Public Function GetArrayMax(a() As Double) As Double
    Dim max As Double, min As Double, i As Integer
    max = a(0)
    min = a(0)
    For i = 1 To UBound(a) - 1
        If max < a(i) Then max = a(i)
        If min > a(i) Then min = a(i)
    Next i
    GetArrayMax = max
End Function

Public Function SSSS()
    Dim ii As Integer, nChannel As Integer, Index As Integer
    Dim xr() As Double
    Dim xi() As Double
    Dim TongDaoShu As Integer, EveryTDPoint As Long
    Dim arrmax As Double
    Writelog "进入循环！"
    Do While (bAIRun)
        Do While (bAIRun)
            If WaitForSingleObject(hEventDRAW, 10) = 0 Then
                Exit Do
            End If
        Loop
        
         'Status = WaitForSingleObject(hEventDRAW, INFINITE)
         If bAIRun = False Then
             Exit Function
         End If
        TongDaoShu = AD_Module.Para.nSampChanCount
        EveryTDPoint = AD_Module.Para.nPointsPerChan
        CurrentIndex = AD_Module.CurrentIndex
        Writelog TongDaoShu & " - " & EveryTDPoint & " - " & CurrentIndex
        
        ReDim xr(EveryTDPoint) As Double
        ReDim xi(EveryTDPoint) As Double
        For Index = 0 To EveryTDPoint - 1 Step 1
        DoEvents
            'Writelog Str(nChannel) + " " + Str(Index) + " " + Str(AD_Module.InUserRegion(nChannel + Index, CurrentIndex))
            For nChannel = 0 To TongDaoShu - 1 Step 1
                xr(Index) = AD_Module.InUserRegion(nChannel + Index, CurrentIndex)
                xi(Index) = 0
            Next nChannel
            Call FFT0(xr(), xi(), EveryTDPoint, 1)
         Next Index
         arrmax = GetArrayMax(xr())
         Writelog Str(arrmax)
         AD_Form.TongDaoHz(nChannel - 1).Caption = arrmax
'        For Channel = 0 To TongDaoShu - 1 Step 1
'            Writelog Channel
'            ReDim xr(EveryTDPoint) As Long
'            ReDim xr(EveryTDPoint) As Long
'            DoEvents
'            For Index = 0 To EveryTDPoint * TongDaoShu - 1 Step TongDaoShu
'                DoEvents
'                xr(Index / TongDaoShu) = AD_Module.InUserRegion(Channel + Index, CurrentIndex)
'                xi(Index / TongDaoShu) = 0
'            Next Index
'            Call FFT0(xr(), xi(), EveryTDPoint, 1)
'            AD_Form.TongDaoHz(Channel).Caption = GetArrayMax(xr())
'        Next Channel
        Writelog "完成循环！"
    Loop
End Function

Public Sub Writelog(ByVal message As String)
'Write Error LogFile

'    Dim ifile As Long
'    ifile = FreeFile
'    Open App.Path & "\log\" & Format(Now, "YYYYMMDD") & ".txt" For Append As #ifile
'    Write #ifile, CStr(Now) & "---(): " & message
'    Close #ifile
     
End Sub

根据阿尔泰叔数据采集卡 USB3200采集数据 得到实时的数字信号波形图   对这个数据做FFT 得到实时频率      例如 每秒采集2048个点  每秒显示一次频率