HP 85108, Системное руководство

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cycle limit is 50 p ercen t, and a v eraging is o. Under these conditions the measuremen t cycle
time is ab out 3 milliseconds p er trace data p oint in the pulse prole domain, or ab out 30
milliseconds in the frequency domain. Figure 3-20 b sho ws the same conditions with a v eraging
on and an a v eraging factor of four. No w four measuremen ts are taken for eac h data p oint with
the measuremen t cycle time alternating b et w een 1 millisecond for eac h of the measuremen ts
required for the a v eraging, and the time to mov e to the next data p oint. Figure 3-20 c sho ws
the measuremen t when 2-P ort correction is On. Here, the parameter switching time also
aects the o v erall PRP and dut y cycle.
Figure 3-20. Example Internal Pulse Output PRP and Duty Cycle
In Figure 3-20 d, the pulse width is greater than the measuremen t cycle time, so the dut y
cycle could approac h 100 p ercen t. This is a v oided b y setting the dut y cycle function to the
maximum v alue allo w ed in the measuremen t. When the com bination of the pulse width
and the dut y cycle limit approac hes the measuremen t cycle time, the pulse o part of the
measuremen t cycle time is increased to satisfy the dut y cycle limit.
If y ou are viewing this with an oscilloscop e, notice ho w the measuremen t cycle time v aries
according to the pulse prole stop time. If the stop time is greater than the pulse width, the
measuremen t cycle time will extend past the end of the pulse dep ending up on the time v alue
of the data p oint b eing measured. Dep ending up on the pulse width, this can result in a low er
p ercen t dut y cycle tow ard the end of the time span.
External Trigger and Stop Sw eep Signals
Figure 3-21 sho ws the relationship b et w een the external T rigger Input and the HP 8510 Stop
Sw eep output for frequency domain p oint-in-pulse measuremen ts and for pulse prole domain
measuremen ts. F or external triggering, Stop Sw eep remains Busy (low) un til the measuremen t
Operation 3-25