NARDA PMM 9010 Series, User Manual

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PMM 9030/9060/9180 Frequency Extension 11-53
11.17.5 Hold Time
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 9030/9060/9180 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 9030/9060/9180
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).
11.17.6 Demodulator
Switching ON the built-in AM demodulator, the volume can be adjusted
with the rotating knob, and the level is shown by the black bar on the
screen.
The demodulated signals can be heard with headphones or earphones
connected to the front panel of the PMM 9010, or amplified and/or
recorded by any suitable device.
An FM demodulator – or other demodulators - is not available for the time
being in the frequency band covered by the PMM 9030/9060/9180.
Insert the headphones jack connector only before switching on the
Demodulator or when the PMM 9010 power is off.