NARDA 8718B, User Manual

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95 Chapter 16 Operation with a Fiber Optic Link
16
Operation with a Fiber Optic Link
Description
Narda fiber optic link transmitters are compatible with all 8700
series probes and the Model 8718B meter. The meter has a
built-in fiber optic receiver compatible with the HP Versatile Link
type plastic cables and connectors. The fiber optic transmitter
connects directly or via a short cable to the probe. A fiber optic
cable connects the 8718B to the transmitter.
The transmitter contains a rechargeable battery that provides
both power for its own circuitry and to operate the amplifier in
the probe. Full system calibration is maintained because each
of the components in the system – meter, fiber optic transmitter,
and probe – are independently calibrated. The fiber optic
transmitter converts the analog DC voltage out of the probe
amplifier to a series of pulses. The pulse rate is directly
proportional to the probe output.
Application
The fiber optic link provides total isolation between the meter and
the probe which is often desirable when making low frequency
measurements. At frequencies below 50 MHz, and especially
below 10 MHz, there is significant interaction between the field,
the individual making the measurements, and the survey
equipment. There is also the possibility that the probe and meter
will be at different electrical potentials which can result in a false
indication of what is actually a scalar field. See Low Frequency
Measurements in the Applications Booklet for additional information.