L3 NARDA PMM 9010 User Manual Download Page 33

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Sweep Mode Operating Instructions

4-5

4.2.2.3 Detector

This menu allows the operator to select the most appropriate

detector

for

the test.
In Sweep mode the Peak, Average, RMS (Root Mean Square) and Quasi-
Peak detectors are available and can be selected via the appropriate button.

Hold time (ms)

The Hold Time (expressed in milliseconds) represents the time the receiver
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. In this case the
PMM 9010 sees a high input signal and therefore tries to set the proper
attenuation automatically increasing the value or the input attenuators.
However, when the input attenuation is set the signal is gone, so the receiver
lowers the attenuation, but then a new peak arrives, and so on and so forth.
On the other hand, if the Hold Time is too high the PMM 9010 cannot
properly follow the signals.
In this situation the

Hold Time

value should be manually set to find a correct

compromise.
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 30 sec (30.000 ms).

4.2.2.4 Smart Detector

The

Smart Detector

is an innovative special function implemented in the

PMM 9010 receiver with the purpose of reducing the test time and increasing
the productivity of the lab.

This function works only when at least one limit is loaded, therefore
remember to enable a limit to run the Smart detector function.

Selecting one out of the three

Smart detectors

the receiver will execute the

scan using at first the Peak detector and, if a peak value is found over the
selected limit minus a

Margin

set with the specific button, the reading is re-

measured and displayed with the chosen (AVG, RMS or QPeak) detector.
Obviously this way of operation results in a much faster scan sweep and
moreover it immediately draws the attention of the test Engineer to the most
critical points. The limit associated to the Margin is displayed as a bold black
line and is automatically selected by the receiver depending which Smart
detector is chosen; for example, if a Smart QP is selected, the associated
QP limit line will be displayed as a bold black line.

The

Smart RMS

detector is disabled until a reference limit is defined by

CISPR.

It is immediately clear that this function is very useful to dramatically reduce
test time and increase the productivity of the test lab.

To deselect the Smart Detector function simply select a single detector.

The weighting time must be properly set in the Hold Time window to
allow the Smart detectors functions to operate as intended.