NARDA PMM 7010 Series, Руководство пользователя

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2-4 Installation
2.11 Using an Artificial
Mains Network
(AMN or LISN)
When the PMM 7010 receiver is connected to a LISN to perform conducted
interference measurements of the EUT, the RF output of the LISN shall be
connected to the RF input of the receiver. In order to switch automatically
between the lines of the LISN, it shall be connected to the User Port of the
receiver thanks to the dedicated cable supplied with the LISN .
If the built-in LISN is to be used, all the connections and commutations are
already done internally and automatically.
Using PMM Emission Suite software it is possible to carry out an automatic
measurement on all mains lines and get the worst case.
In order to avoid the unwanted tripping of the protection devices, an
insulation transformer shall always be used between the mains supply
and a LISN.
2.12 Using the Pulse
Limiter
The built in pulse limiter is a useful device to protect the input of the receiver
from transient over voltages. Sometime the conducted disturbances entering
the receiver through the LISN are too high - even if they cannot be seen on
the PMM 7010 because they are out of measurement bandwidth - and the
associate energy is high enough to damage the input circuit.
The pulse limiter has been integrated in the system as a protection of the
input from unexpected pulses.
When using an external Artificial Mains Network, to reduce the
probability of damages caused by transient voltage pulses always
disconnect the PMM 7010 RF input before switching Equipment Under
Test supply ON or OFF.
2.13 Using Current and
Voltage Probes
When a LISN cannot be used – e.g. when measurements have to be made
on terminals other than the mains ones, such as load or command terminals,
sensitive to inserted capacities for example, or when LISNs of adequate
current capabilities aren’t available, or when the line voltage is too high – a
current or voltage probe can be used.
The characteristics of these probes, and some advises on their uses, are
given in §5 of CISPR 16-1-2.
The CISPR voltage probe contains a resistor with a minimum resistance of
1500 ohm, in series with a capacitor of negligible reactance vs. the resistance
(in the 150 kHz to 30 MHz range), and it is insulated at least up to 1500V.
All these probes have an insertion loss and a frequency response that can be
stored in the PMM Emission Suite, so that the actual readings of the receiver
can be automatically corrected by these characteristics values.
2.14 Using Antennas
and other
Transducers
In the frequency range from 9 kHz to 1000 MHz any other transducer can be
used to pick-up and measure RF conducted and radiated emissions, like
active and passive loop antennas, rod, dipole, biconical and log periodic
antennas, near field probes etc.
The characteristics of these transducers are usually specified in the relevant
standards (e.g. Military or Automotive Standards).
Their use with PMM 7010 is very easy, as it’s enough to enter their response
with the frequency into the memory of the PMM Emission Suite to have the
readings automatically corrected. When the cable is not calibrated together
with the transducer, even the cable loss can be entered.
Up to four factors can be used together at the same time.