L3Harris NARDA PMM ER8000 User Manual page 34

The Hold Time (expressed in milliseconds) represents the time the receiver
3.5 Hold Time
uses to "take a snapshot" of the incoming signal and to measure it with the
chosen detector. When selecting a detector, the default hold time value is
automatically loaded, but in some cases this time is not appropriate, e.g. when
the interference signals have a low repetition rate or when the standard
impose a proper measurement time.
In case of low repetition pulsed disturbances, a too short hold time may cause
the automatic input attenuator to change its setting everytime the pulsed
incoming disturbance appears or disappears.
On the other hand, if the Hold Time is too long, the length of the measurement
increases without having any useful effect.
In this situation, the Hold Time value should be manually set to find a correct
compromise between test precision and duration. That is to say choosing a
Hold Time long enough for the lower repetition rate of the supposed
disturbance and to keep the measurement length within a practical duration.
To set the Hold Time to the lowest possible value (this value dynamically
depends from the measurement conditions), enter the figure 0; if a value lower
than the allowed is entered, the lowest possible value is automatically
selected.
The max. Hold Time that can be set is 120 sec (120.000 ms).
Be sure not to overload PMM ER8000: the input signal should not exceed
the maximum level indicated in the main specifications in chapter 1.
The measuring time must be properly set in the Hold Time window to
allow the desired detectors to operate as intended.
3-6 Operating Instructions