Simulated Eye Diagram

Dim rm As VisaComLib.ResourceManager

Dim vna As VisaComLib.FormattedIO488

Sub Message(msg As String)

    Dim NumDmy As Integer

    'Syncronize to VNA

    vna.WriteString "*OPC?"

    NumDmy = vna.ReadNumber

    'Write Message

    MsgBox msg, vbOKOnly

End Sub

Sub SimEyeDiagram()

    On Error GoTo errorhandler

    Set rm = New VisaComLib.ResourceManager

    Set vna = New VisaComLib.FormattedIO488

    ' Set your VNA address

    Set vna.IO = rm.Open("TCPIP0::K-N5232B-40046::hislip0::INSTR")

    vna.IO.Timeout = 90000

    ' Clear Excel Sheet Cells

    Range("A1:F22").ClearContents

    With vna

        Dim i As Integer

        ' Set DUT Topology to Differential 2-Port

        .WriteString ":CALC:TDR:DEV DIF2"

        ' Execute Deskew using TDR Setup Wizard

        .WriteString ":DISP:TDR:MIN:STAT OFF"

        Message "[Deskew]" + vbCrLf + _

                "1. Press 'TDR Setup Wizard' on TDR GUI." + vbCrLf + _

                "2. Select 'Deskew' and complete the wizard with 'Finish' button." + vbCrLf + _

                "3. Confirm 'TDR [Deskew]' indicator appears on VNA status line." + vbCrLf + _

                "4. Press OK button to continue."

        ' Minimize TDR GUI

        .WriteString ":DISP:TDR:MIN:STAT ON"

        ' Set Rise Time

        .WriteString "CALC:PAR:COUN?" 'Get number of traces

        For i = 1 To .ReadNumber

            .WriteString ":CALC:TDR:MEAS" + CStr(i) + ":TIME:STEP:RTIM:THR T2_8" 'Threshold

            .WriteString ":CALC:TDR:MEAS" + CStr(i) + ":TIME:STEP:RTIM 50e-12"   'Rise Time

        Next i

        ' Set Bit Pattern Parameters

        .WriteString ":CALC:TDR:EYE:INP:BPAT:TYPE PRBS" 'Type

        .WriteString ":CALC:TDR:EYE:INP:BPAT:LENG 7"    'Length

        .WriteString ":CALC:TDR:EYE:INP:OLEV 200e-3"    'One Level

        .WriteString ":CALC:TDR:EYE:INP:DRAT 1e9"       'Data Rate

        ' Set Rise Time/Threshold

        .WriteString ":CALC:TDR:EYE:INP:RTIM:DATA 50e-12"

        .WriteString ":CALC:TDR:EYE:INP:RTIM:THR T2_8"

        ' Activate Trace 5 (Tdd21)

        .WriteString ":CALC:PAR:MNUM:SEL 5"

        ' Execute Draw Eye

        Message "Connect DUT to cables." + vbCrLf + "Press OK to draw Eye diagram."

        .WriteString ":CALC:TDR:EYE:STAT ON"

        .WriteString ":CALC:TDR:EYE:EXEC"

        ' Read Eye Results

        Cells(3, 4) = "Eye Results"

        Dim Labels() As Variant

        Labels = Array("Min. Value", "Max. Value", "Level Zero", "Level One", "Level Mean", "Amplitude", "Height", "(Reserved)", "Width", "Opening Factor", _

             "Signal/Noise", "Duty Cycle Dist", "Duty Cycle Dist(%)", "Rise Time", "Fall Time", "Jitter p-p", "Jitter RMS", "Crossing %")

        Dim EyeResult() As Double

        .WriteString ":CALC:TDR:EYE:RES:DATA?"

        EyeResult() = .ReadList(ASCIIType_R8, ",")

        For i = 0 To 17 'Number of results = 18

            Cells(i + 5, 4) = Labels(i)

            Cells(i + 5, 6) = EyeResult(i)

        Next i

        ' Restore TDR GUI

        .WriteString ":DISP:TDR:MIN:STAT OFF"

        Message "Finished Simulated Eye Diagram."

    End With

    vna.IO.Close

    Exit Sub

errorhandler:

    MsgBox Err.Description, vbExclamation, "Error Occurred", Err.HelpFile, Err.HelpContext

End Sub