User guide

Termination
In this field, enter the termination voltage that is appropriate for the incoming data
signal. This selection should be made before the device is connected to the
analyzer.
If the input is set to differential mode, a termination voltage can only be set for a
device that is DC-connected.
C A U T I O N
Selecting the wrong terminations may damage your device.
The Data In port is connected to a 50 Ohm load impedance (or termination) within
the error detector. Data termination refers to the voltage level at the end of this
load. The logic output from a device requires any connected equipment, including
the error detector, to have a specific termination voltage.
Input Range
Before you can synchronize the error detector to the incoming data stream, you
need to define the voltage range within which the eye is located.
Both the high and low level of the data signal must be within this range to find the
eye.
N O T E
The input voltage range is 2V. When you modify either the high or low voltage, the
other voltage is automatically adjusted.
N O T E
See “Sampling Point Setup - Reference” on page 198 for a complete description of
all parameters of the Sampling Point Setup window.
Clock Setup
Clock Setup - Concepts
To measure the Bit Error Rate with the error detector, the bit rate of the data stream
must be known. Depending on the options the instrument is delivered with, you
could use either an external clock source for the error detector (for example, the
Setting up the Error Detector 5
Agilent J-BERT N4903B High-Performance Serial BERT 173