User guide

Data Input Setup - Reference
The ED Input Setup dialog is accessed from the Sampling Point Setup window. It
is used to set up the error detector's data input port:
Input
The selection in this list defines how the signals arriving at the Data In and Data
In connectors are interpreted. The following options are available:
• Differential
If differential mode is selected, both input ports need to receive a signal. The
actual data signal is measured as the voltage difference between the two
incoming signals.
•
Normal
In normal mode, only the Data In port receives the data signal, the Data In port
is inactive.
•
Complement
In complement mode, only the Data In port receives the data signal, the Data
In port is inactive.
Data Inverted
Activate this checkbox to invert the polarity of the error detector reference pattern.
This function is required if your device inverts data.
Threshold
Only available, if the input is set to normal or complement mode.
Choices are:
• Averaging: The 0/1 threshold voltage is derived from the input signal via a low-
pass filter. This will work fine for most applications.
• Manual input: Enter a value for applications that do not provide a continuous
data stream at the input (for example, any application using bursts), because
the averaged 0/1 threshold voltage will drift from the correct level when there
is no input. The manually set threshold voltage must of course be within the
input range.
5 Setting up the Error Detector
172 Agilent J-BERT N4903B High-Performance Serial BERT