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Introduction to the System
Timing Principles
Synchronization of Signals
Several features support the synchronization of signals.
Zero Adjust, Cable and Propagation Delay Compensation
With the HP 81200 system it is possible to synchronize the outputs and
inputs of newly installed frontends or new modules.
To assure that all generator output signals are applied at the same time
either at the DUT board or even at the DUT input pins it is possible to
perform a cable delay and propagation delay compensation.
The procedures are menu driven and semi-automatic.
Negative Delay
Apart from synchronizing signals it might be interesting and important to
have some signals applied in advance to other signals.
Therefore the HP 81200 system provides the option to set a general time
offset for all connectors, so that individual ones can be set to negative
delays and hence start earlier than others.
The delay offset feature can be used in Setup and Hold time
measurements.
Trigger-Controlled Start and Stop
The EXT INPUT of the clock module can be used to start and stop the
timing system of the HP 81200. The state of this input is sampled once a
system period. If the CLOCK/REF INPUT is used as External Clock Source,
this is the system period.
When using the EXT INPUT without an External Clock Source at the
CLOCK/REF INPUT, the signal must be applied for a time greater than the
system period.
When using the EXT INPUT with an External Clock Source at the
CLOCK/REF INPUT, setup and hold time must be considered for
predictable timing.
N O T E
Setup and hold time violations may influence the HP 81200 System only in
the aspect that the system will generate consistent relative timings for data
generation and data capture, but the absolute timing, related to the
external input, may vary of about ±1 system period.
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HP 81200 Data Generator/Analyzer Platform User Guide, Revision 2.1
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