Technical data

85108L System Manual
Operation
Pulsed-RF Applications
3-25
Each measurement cycle is initiated by the falling edge of the TTL signal at the rear panel external
Trigger Input, or the internal 8510 logic, depending on whether external or internal triggering is
selected. At the appropriate time after the trigger, the measurement is made. If averaging is turned
On but not completed, the process waits for the next trigger to make the next measurement for that
data point. If averaging is complete but another parameter is required (2-Port correction is On), the
next parameter is selected and the process waits for the next trigger. When all data for that point is
acquired, the process moves to the next point, changing the frequency (if in the frequency domain),
or the time (if in the pulse profile domain), then waits for the next trigger.
These times are representative typical measurement cycle times using preset values for the
analyzer controls.
Measurement Cycle Times
Controls that can affect the measurement cycle time are:
Sweep Time When the analyzer is otherwise ready for the next measurement
cycle, it ignores triggering for an interval equal to (Sweep Time
(ms)/Number of Points).
Pulse Width The pulse always remains On for the user-specified time.
Duty Cycle Limit When the analyzer is otherwise ready for the next measurement
cycle, if the Duty Cycle percent maximum limit would be
exceeded, the process ignores triggering until the duty cycle
limit is satisfied.
Pulse Profile Domain Stop
Time The time value of the current pulse profile data point
determines the measurement cycle time when it is greater than
the PRP set by the duty cycle limit.
Frequency Domain Trigger
Delay If the Frequency domain Trigger Delay is greater than the duty
cycle limit, trigger delay will control the minimum frequency
domain measurement cycle time.
The only additional considerations are:
1. Pulse Output is set to the active level during measurement of any calibration standard.
2. It is set to the inactive level during the sweep retrace.
3. It is set to the active level for less than 30 microseconds immediately prior to the beginning of
the sweep for the automatic periodic IF calibration sequence.
4. It remains at the inactive level under all conditions when External Triggering is selected.
The automatic periodic IF calibration sequence is transparent to the operator except for the less
than 30 microsecond pulse output prior to the beginning of a sweep. To the operator, the IF
calibration sequence will appear to occur at random times, more frequently just after the 8510 is
turned on, then less often as the system temperature stabilizes.
1 ms Next Average
4 to 8 ms Next Parameter
(Frequency Domain)
30 to 40 ms Next Frequency Point
(Frequency Domain)
3-4 ms Next Time Point
(Pulse Profile Domain)