B Theory of Operation

Overall Functional Description

The meter is a portable, battery-operated instrument that forms a complete RF Radiation Survey System when used with an interconnected Narda 8700 Series probe. Optionally, the system may employ a fiber optic transmitter and cable between the probe and meter. The survey system is designed to detect electromagnetic fields and to display the field level on the meter’s Liquid Crystal Display (LCD). The probe detects the electromagnetic radiation and transmits a DC signal to the meter. The meter processes the signal from the probe for viewing on the LCD screen. The meter displays the field levels in various units of measure dependent on the field component detected and the characteristics of the probe used.

Probe Functional Description

The probe senses the electromagnetic fields and develops a signal for transmission to the meter. The probe has an isotropic sensing pattern so that the radiation may be sensed from any direction, except through the handle. Detectors in the probe sense the electromagnetic radiation present and apply signals to preamplifiers U1 and/or U2 located within the probe. Preamplifiers U1 and U2 amplify the signals from the detectors and route them to the meter via connector P1.

Model 8718B Meter Functional Description

The meter receives the signal(s) from the probe, processes the signal(s) and provides a visual display of the levels detected. The signal(s) received from the probe at PROBE connector J1 is routed to amplifier U2. Amplifier U2 amplifies the signal(s) from the probe and generates a signal to drive the A/D converter U3. The output of the A/D converter is routed to microprocessor U5 that drives the LCD.

Appendix B Theory of Operation

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