NARDA PMM ER9000, User Manual

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3-14 Operating Instructions
3.2.3.8 Misc
Under the Miscellaneous functions menu it is possible to activate or exclude
the Preselector filters, the Pulse Limiter , and also to set the internal Signal
generator .
The
Preselector is composed by a group of filters automatically selected by
the PMM ER9000 while it is sweeping or anyway measuring. The aim of the
preselector is to reduce the amount of out-of-band energy entering in the
receiver, thus helping a lot in reducing intermodulation problems and similar
undesired behaviors.
It can be set either ON or OFF with the associated button, and normally it
should be always enabled.
On the middle top of the screen, the indication “Presel” is displayed when
active.
The
Pulse Limiter is a very useful device to protect the input of the receiver
from transient overvoltages. Doing conducted emission tests, quite often there
are conducted disturbances (usually associated to switching operations in the
EUT or along the line under test) which are too high and that propagates
through the LISN up to the receiver. Sometime these disturbances cannot be
seen on the receiver because they are out of measurement bandwidth,
nevertheless the associate energy is high enough to damage the input
attenuator and/or the Analog-to-Digital Converter of the PMM ER9000 (the first
mixer in a traditional receiver).
This pulse limiter has an integrated 30 MHz low-pass filter.
When the Pulse Limiter is selected, on the upper right part of the screen the
letters
PL appear and the reading on the receiver is automatically corrected for
the presence of the Pulse Limiter.
Touching the
RF OUT button, the receiver enters the Signal generator menu.
The
signal generator is an internal, high stability and accuracy, 50 Ohm RF
generator ranging from 10 Hz to 30 MHz.
In Manual Mode only, it can be set to operate as a tracking generator. When
Tracking On function is selected, the generator is always tuned at the same
PMM ER9000 measurement frequency, and scans the range together with the
receiver. This is the standard way a tracking generator works in all spectrum
analyzers.
If the Tracking On function is disabled, the generator becomes a CW signal
source tuned at the frequency set under the
RF OUT Freq window.
As usual, to set a given frequency it is therefore enough to edit the value with
the software keys, confirming the selections entering the units value (Hz, kHz,
MHz or GHz).
In both operating modes (tracking or fixed frequency) the output level can be
set between 60,0 and 90,0 dBµV with 0,1dB steps using the
RF OUT Level
button.
If a higher or lower level is needed, the User shall adopt either an external
amplifier or an external attenuator.