'--- DVB QPSK a MPEG QPSK Calculator 7/26/99 8:37:01 AM ---

'--- Directives ---
$APPTYPE GUI
$TYPECHECK ON
$INCLUDE "RAPIDQ.INC"

'--- Declarations ---
DECLARE FUNCTION doubleSTR (Number AS DOUBLE#, N1 AS INTEGER) AS STRING
DIM frmDvbQpsk AS QFORM
DIM btnQuit AS QBUTTON
DIM btnHelp AS QBUTTON
DIM btnAbout AS QBUTTON
DIM lblFec AS QLabel
DIM cmbFec AS QComboBox
DIM btn188Rate AS QBUTTON
DIM edt188Rate AS QEDIT
DIM btn204Rate AS QBUTTON
DIM edt204Rate AS QEDIT
DIM btnSymbolRate AS QBUTTON
DIM edtSymbolRate AS QEDIT
DIM btnBw AS QBUTTON
DIM edtBw AS QEDIT

'--- global variables ---
DIM P AS INTEGER
P = 3
DIM Fec as Double
Fec = .5000
DIM Rate188 as Double
DIM Rate204 as Double
DIM RateSymbol as Double
DIM Bw as Double

'--- Sub and Func ---

'--- exit application ---
SUB DoQuit
    frmDvbQpsk.Close
END SUB

'--- help message ---
SUB DoHelp
    SHOWMESSAGE "Select FEC and enter a known parameter." +CHR$(13) +_
    "Click the button associated with the known" + CHR$(13) + " parameter to calculate all parameters."
END SUB

'--- about message ---
SUB DoAbout
    SHOWMESSAGE "DVB QPSK is a simple calculator provided to" + CHR$(13) + _
                                "aid in the setup of DVB digital video transmitters and IRD's." + CHR$(13) + _
                                CHR$(13) + _
                                "Freeware by E.J. Livaditis" +CHR$(13) + _
                                "Developed with RAPID-Q by William Yu"
END SUB

'--- select Fec ---
SUB ItemChanged
    Select Case cmbFec.ItemIndex
        Case 0
            Fec = .50000
        Case 1
            Fec = .66666
        Case 2
            Fec = .75000
        Case 3
            Fec = .83333
        Case 4
            Fec = .87500
    End Select        
END SUB

'--- calculate using FEC and 188 byte transport rate ---
SUB Crunch188
    IF (edt188Rate.Text = "") then
        DoHelp
        EXIT SUB
    END IF
    Rate188 = VAL(edt188Rate.Text)
    Rate204 = 204/188 * Rate188
    RateSymbol = (Rate204 * 1/Fec * .5)
    Bw = RateSymbol * 1.35
    edt204Rate.Text = doubleSTR(Rate204,3)
    edtSymbolRate.Text = doubleSTR(RateSymbol,3)
    edtBw.Text = doubleSTR(Bw,3)
END SUB

'--- calculate using FEC and 204 byte transport rate ---
SUB Crunch204
    IF (edt204Rate.Text = "") then
        DoHelp
        EXIT SUB
    END IF
    Rate204 = VAL(edt204Rate.Text)
    Rate188 = 188/204 * Rate204
    RateSymbol = Rate204 * 1/Fec * .5
    Bw = RateSymbol * 1.35,P
    edt188Rate.Text = doubleSTR(Rate188,3)
    edtSymbolRate.Text = doubleSTR(RateSymbol,3)
    edtBw.Text = doubleSTR(Bw,3)
END SUB

'--- calculate using FEC and symbol rate ---
SUB CrunchSymbol
    IF (edtSymbolRate.Text = "") then
        DoHelp
        EXIT SUB
    END IF
    RateSymbol = VAL(edtSymbolRate.Text)
    Rate188 = RateSymbol / (204/188 * 1/Fec * .5)
    Rate204 = 204/188 * Rate188
    Bw = RateSymbol * 1.35
    edt188Rate.Text = doubleSTR(Rate188,3)
    edt204Rate.Text = doubleSTR(Rate204,3)
    edtBw.Text = doubleSTR(Bw,3)
END SUB

'--- calculate using FEC and BW (bandwidth) ---
SUB CrunchBw
    IF (edtBw.Text = "") then
        DoHelp
        EXIT SUB
    END IF
    Bw = VAL(edtBw.Text)
    RateSymbol = Bw / 1.35
    Rate188 = RateSymbol / (204/188 * 1/Fec * .5)
    Rate204 = 204/188 * Rate188
    edt188Rate.Text = doubleSTR(Rate188,3)
    edt204Rate.Text = doubleSTR(Rate204,3)
    edtSymbolRate.Text = doubleSTR(RateSymbol,3)
END SUB

'--- a function to round off double to N1 places and converts it to string ---
FUNCTION doubleSTR(Number AS DOUBLE#, N1 AS INTEGER) AS STRING
    DIM NumStr as STRING
    DIM rr as DOUBLE
    DIM nn as DOUBLE
    DIM dp as INTEGER
    rr = INT(10^N1 + .5)
    nn = INT(rr * Number + .5)
    NumStr = STR$(nn/rr)
    dp = instr(NumStr,".")
    if (dp = 0) then
        dp = len(NumStr) + N1
    else
        dp = dp + N1
    end if
    doubleSTR = LEFT$(NumStr,dp)
END FUNCTION

'--- main form setup ---
frmDvbQpsk.BorderStyle = bsToolWindow
frmDvbQpsk.Center
frmDvbQpsk.Caption = "DVB QPSK  By EJsoft"
frmDvbQpsk.Height = 205
frmDvbQpsk.Width = 260

btnQuit.Parent = frmDvbQpsk
btnQuit.Left = 50
btnQuit.Top = 10
btnQuit.Width = 40
btnQuit.Caption = "&Quit"
btnQuit.OnClick = DoQuit

btnHelp.Parent = frmDvbQpsk
btnHelp.Left = 110
btnHelp.Top = 10
btnHelp.Width = 40
btnHelp.Caption = "&Help"
btnHelp.OnClick = DoHelp

btnAbout.Parent = frmDvbQpsk
btnAbout.Left = 170
btnAbout.Top = 10
btnAbout.Width = 40
btnAbout.Caption = "&About"
btnAbout.OnClick = DoAbout

lblFec.Parent = frmDvbQpsk
lblFec.Left = 10
lblFec.Top = 50
lblFec.Width = 40
lblFec.Caption = "FEC"

cmbFec.Parent = frmDvbQpsk
cmbFec.Left = 10
cmbFec.Top = 70
cmbFec.Width = 45
cmbFec.AddItems "1/2", "2/3", "3/4", "5/6", "7/8"
cmbFec.ItemIndex = 0
cmbFec.OnChange = ItemChanged

btn188Rate.Parent = frmDvbQpsk
btn188Rate.Left = 60
btn188Rate.Top = 50
btn188Rate.Width = 120
btn188Rate.Caption = "&188 Byte Rate Mbps"
btn188Rate.OnClick = Crunch188

edt188Rate.Parent = frmDvbQpsk
edt188Rate.Left = 190
edt188Rate.Top = 52
edt188Rate.Width = 50

btn204Rate.Parent = frmDvbQpsk
btn204Rate.Left = 60
btn204Rate.Top = 80
btn204Rate.Width = 120
btn204Rate.Caption = "&204 Byte Rate Mbps"
btn204Rate.OnClick = Crunch204

edt204Rate.Parent = frmDvbQpsk
edt204Rate.Left = 190
edt204Rate.Top = 82
edt204Rate.Width = 50

btnSymbolRate.Parent = frmDvbQpsk
btnSymbolRate.Left = 60
btnSymbolRate.Top = 110
btnSymbolRate.Width = 120
btnSymbolRate.Caption = "&Symbol Rate Msps"
btnSymbolRate.OnClick = CrunchSymbol

edtSymbolRate.Parent = frmDvbQpsk
edtSymbolRate.Left = 190
edtSymbolRate.Top = 112
edtSymbolRate.Width = 50

btnBw.Parent = frmDvbQpsk
btnBw.Left = 60
btnBw.Top = 140
btnBw.Width = 120
btnBw.Caption = "-20 dB &Bandwidth MHz"
btnBw.OnClick = CrunchBw

edtBw.Parent = frmDvbQpsk
edtBw.Left = 190
edtBw.Top = 142
edtBw.Width = 50

frmDvbQpsk.ShowModal