HP 54750A, User Manual, Page: 433 / 478

How the Instrument W orks
System Architecture
Suppose you are trying to debug an intermittent failure in a state machine
that is implemented in high-speed CMOS logic. Y ou know you need a
high-performance digitizing analyzer , but you don't know which probe gives
the best results .
There are two major factors inuencing probe selection:
1. the load the probe imposes on the circuit
2. the required bandwidth of the circuit with the probe
Probe loading Figure 13-7 shows a simplied diagram of the circuit with the probe attached
to indicate the principal loading eects . The probe load has both resistive
and capacitive components . In addition to this , the inductance in the probe
ground lead can cause ringing.
Figure 13-7. Simplied equivalent circuit of DUT and probe.
13-13