Technical data

Controlling the Output Levels
Controlling the Output Levels - Concepts
When the output levels are changed at the Serial BERT's data and clock output
ports, four parameters are changed:
• V
hi
• V
lo
• V
ampt
• V
offs
The Serial BERT groups these parameters into "pairs" (V
ampt
/V
offs
, V
hi
/V
lo
). If one
of these values is modified, its "partner" remains constant, and the values in the
other pair are modified accordingly. For example, if V
ampt
is changed, V
offs
stays
constant, and V
hi
and V
lo
are modified accordingly.
Controlling the Output Levels - Procedures
The IVI-COM driver provides a convenient function for setting V
ampt
and
V
offs
: Configure . To set the pattern generator's data output voltage:
Private Sub SetPGDataOutVolt()
Dim myPG As AgilentN490xLib.IAgilentN490xPG
Dim myPGOut As AgilentN490xLib.IAgilentN490xPGOutput
Set myPG = myBERT.PGs.Item("PG1")
Set myPGOut = myPG.Outputs.Item("PGOutput1")
myPGOut.OutVoltage.Configure 1.5, 0.5, _
myPGOut.OutVoltage.VTermination
End Sub
The following command shows how you would set the data output so that it has
an amplitude of 1.5V and an offset of 0.5 V :
SOUR:VOLT:AMPL 1.5; OFFS 0.5
This sets the output accordingly (V
Hi
= 1.25 V, V
Lo
= -0.25).
Conversely, you could set V
Hi
and V
Lo
directly:
SOUR:VOLT:HIGH 1.25; LOW -0.25
Recommended Programming Techniques 3
Agilent J-BERT N4903B High-Performance Serial BERT 21
Changing the Voltages with IVI-
COM
Changing the Voltages with SCPI