ETS-Lindgren FP2083 Isotropic Electric Field Probes (Archived) - Manual (Page 17)

Isotropic Electric Field Probes
HI-4453/FP5083/FP4083/FP2083
© ETS-LINDGREN L.P. – June 2005
Rev. F, P# H-600064 17
PROBE OPERATION
Receiver commands to the probe consist of the following:
• Send reading
• Read battery voltage
• Zero
• Set sleep timer
• Switch range
• Read
temperature
• Enable
axis
The signal flow within the probe is shown in the block diagram.
To measure field strength, three mutually orthogonal dipole
antennas (one per axis) are used to provide an isotropic
response to the ambient field. The signal from each axis is fed
to a Schottky diode detector operating in its Square-Law region.
After filtering, the signals generated by each axis are fed to the
instrumentation amplifier, whose output feeds the selectable
range/offset stage.
For each of the four ranges, the selectable range and offset
stage provides a coarse analog zero for the measured signal.
The output of the range/offset stage is fed to the A/D multiplexer,
then to the analog-to-digital (A/D) converter itself.
After acquiring the composite three-axis signal, the
microprocessor commands the A/D multiplexer to read the
battery voltage and temperature sensing lines. Data from the
A/D converter is fed to the microprocessor, which transmits it to
the receiver.
The EEPROM stores all calibration data for the probe.
Archived 4/2/10