Fourier via Excel VBA

Function CFourier_fix_coef(w_B, addr_cell) As Double

'Const Ts As Double = 1 / 1200
Dim C(24) As Double

    ' Цикл для вычисления коэффициентов
    For i = 1 To 24
        C(i) = Sin((i - 1) * w_B / 1200)
    Next i

    ' Цикл для вычисления орт.сост.
    a = 0
    If Range(addr_cell).Row < 24 + 3 Then
        start_row = 28 - Range(addr_cell).Row
    Else
        start_row = 1
    End If
    For i = start_row To 24
        x = Range(addr_cell).Offset(i - 24, 0)
        'If IsNumeric(x) Then
            a = a + x * C(i)
        'End If
    Next i

    a = a * 2 / 24

    CFourier_fix_coef = a

End Function

Function SFourier_fix_coef(w_B, addr_cell) As Double
Dim S(24) As Double

    ' Цикл для вычисления коэффициентов
    For i = 1 To 24
        S(i) = Cos((i - 1) * w_B / 1200)
    Next i

    ' Цикл для вычисления орт.сост.
    a = 0
    If Range(addr_cell).Row < 24 + 3 Then
        start_row = 28 - Range(addr_cell).Row
    Else
        start_row = 1
    End If
    For i = start_row To 24
        x = Range(addr_cell).Offset(i - 24, 0)
        'If IsNumeric(x) Then
            a = a + x * S(i)
        'End If
    Next i

    a = a * 2 / 24

    SFourier_fix_coef = a

End Function