ETS-Lindgren HI-3520 Microwave Monitor (Archived) - Manual (Page 16)

Page 12 HI-3520 Manual
The analog output from the DC amplifier is digitized by
the microcontroller's A/D converter. The reference
voltage for the A/D converter is generated from a band-
gap reference diode which provides excellent long term
stability. The microcontroller then controls the
measurement rate for instantaneous or average
measurements, amplifier ranges. LCD display, fault
indications and low battery signals. It store and
computes the data for the six minute average readout and
stores the alarm warning level trip point.
4.3 RF Shielding
To enable accurate operation of the sensitive circuits
within the RF Radiation Badge in the presence of RF
fields, an array of shielded and absorbers is used. The
circuits are contained within a Faraday shielded area
which is then covered by a graded absorber to minimize
field disturbances. To prevent reflections from behind the
unit giving distorted measurements results, the antenna
section is protected by an absorber. The net result is
that the sensitivity to any reflection from the rear of the
unit is minimized relative to its performance in free space.
Archived 4/2/10