26
Keysight M8070A Programming Guide
2
Recommended Programming Techniques
Output Protection
Pattern Generator Output Termination
The pattern generator's output ports must be terminated with 50
Ω
if they
are not connected. Termination of output ports improves the test
performance.
Output Protection Algorithm
The instrument has an internal protection algorithm that protects the
instrument from improper termination of the pattern generator's output
ports.
The algorithm checks whether the termination voltage and termination
resistance are correct before the output is enabled. This check happens
once only.
In non-balanced dc coupled mode, the termination voltage must be within
± 0.1 V of the specified value. The resistance must be between 40 and
60
Ω
.
In balanced mode, the resistance must be between 80 and 120
Ω
(differential termination).
In ac coupled mode, which is intended for balanced only (for example,
8b/10b coded patterns), the output is enabled if no termination voltage
and no termination resistance are detected. This is the case if ac
capacitors are in front of the outputs. The check distinguishes between a
terminated or an open output.
NOTE
Refer also to the M8020A/M8030A/M8040A Getting Started Guide for
information on terminating the M8061A outputs to ensure proper
performance.
NOTE
Do not operate the output driver into an open.