NARDA PMM ER9000, User Manual

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Operating Instructions 3-9
3.2.3 MANUAL MODE
The MANUAL mode is a very useful feature to manually control the receiver
and to deeply investigate electrical signals modifying the parameters of
receiver exactly as per the needs of the Test Engineer.
In this operating mode, the instrument continuously display the signal level at a
desired fixed frequency (not sweeping).
It is possible, for example, to observe the signals exceeding the limits
frequency by frequency; evaluating their levels measured simultaneously with
4 different detectors (Peak, QuasiPeak, Average and RMS); listening to them
after a demodulation, etc.
To enter in
Manual Mode touch the key in the main menu, and immediately
the first Manual window opens.
In manual mode, the levels corresponding to the detectors in use are displayed
both in analogue and in digits format and, exactly as for the other operating
modes, all the relevant information are reported on the screen.
The User can see the resolution bandwidth, the longest hold time associated
to the detectors in use; if the input attenuation is Automatic or Manual and the
set attenuation and the Minimum attenuation.
Also the Demodulator can be switched on and set to AM or FM, and the audio
volume regulated as wished and represented by a simple bar.
Then there are three up to six vertical bars representing the detectors and
indicating in analogue and digital (the figures below each bar) the level
measured; on top of the bars the relevant detector, the unit in use and the
tuned frequency. The analogue scale of the analogue bars is set automatically
by the firmware, in accordance with the Reference Level.
In case an OVERLOAD indication occurs it is necessary to add an
external attenuator to carry on the measurement without overpassing the
declared limit for continuous power or spectral density.
Using 0 dB attenuation PMM ER9000 has no input protection.
This is a potentially dangerous condition for the input stage of the
receiver.
Use 0 dB attenuation only if you are very sure that your input signal is
less than 1 Vpp (or 120 dB
µ
V).
Before to apply an unknown signal to PMM ER9000 receiver, use an
oscilloscope or a wide band RF voltmeter to measure it. In any case set
Min. ATT at 10 dB and select the maximum available attenuation.
If needed, add an external coaxial attenuator on the input signal line.