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Chapter 6 Application Programs
Program Listings
4
6
Example: Amplitude Modulation
This program (found in the “Examples\chapter6\AMLowLevel” subdirectory on the CD-
ROM) configures a waveform with amplitude modulation using lower-level SCPI
commands. It also shows how to use the *SAV command to store the instrument
configuration in the function generator’s internal memory.
Private Sub cmdAMLowLevels_Click()
Dim io_mgr As VisaComLib.ResourceManager
Dim Fgen As VisaComLib.FormattedIO488
Set io_mgr = New VisaComLib.ResourceManager
Set Fgen = New VisaComLib.FormattedIO488
Set Fgen.IO = io_mgr.Open(txtIO.Text)
On Error GoTo MyError
' This program uses low-level SCPI commands to configure
' the function gnerator to output an AM waveform.
' This program also shows how to use "state storage" to
' store the instrument configuration in memory.
With Fgen
.WriteString "*RST" ' Reset the function generator
.IO.Clear ' Clear errors and status registers
.WriteString "OUTPut:LOAD 50" ' Output termination is 50 Ohms
.WriteString "FUNCtion:SHAPe SINusoid" ' Carrier shape is sine
.WriteString "FREQuency 5000;VOLTage 5" ' Carrier freq is 5 kHz @ 5 Vpp
.WriteString "AM:INTernal:FUNCtion SINusoid" ' Modulating shape is sine
.WriteString "AM:INTernal:FREQuency 200" ' Modulation freq = 200 Hz
.WriteString "AM:DEPTh 80" ' Modulation depth = 80%
.WriteString "AM:STATe ON" ' Turn AM modulation on
.WriteString "OUTPut ON" ' Turn on the instrument output
.WriteString "*SAV 1" ' Store state in memory location 1
' Use the "*RCL 1" command to recall the stored state
End With
Exit Sub
MyError:
txtError = Err.Description & vbCrLf
Resume Next
End Sub
33210A users guide.book Page 303 Wednesday, July 16, 2008 11:16 AM
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