Harris Atlas DVL400, Technical Manual

Page: 129 / 180

2/25/03 888-2473-001 4-29
WARNING: Disconnect primary power prior to servicing.
Section 4 Theory of Operation
ATLAS Series™
The comparator fault thresholds are set using "EEPOTS". These are basically
programmable electronic potentiometers that are being programmed by the micro
module based on the lookup table mentioned above.
Example: (Note: The following values are used for example only)
At a reference frequency of 600MHz, 50mW of RF input = 3Vdc detected output
At a transmitter frequency of 500MHz, 50mW of RF input = 3.4Vdc detected
output
When the GUI is configured for a transmitter frequency of 500MHz, the micro
module on the RF Monitor board receives this information. The micro module
would then
look up the 500MHz frequency in the table and set the fault threshold of
the comparator (using the EEPOT) for 3.4Vdc instead of the 3Vdc used at the
reference frequency.
The comparator is now calibrated to trip when 500W is applied to the reject load
being monitored without having to re-calibrate the detector.
4.4.6.2.2 PA Module Phase Alignment
The outputs of the reject load detectors are also multiplexed into a 10bit ADC
(Analog to Digital Converter) on the micro module. The ADC output will be
between 0 and 1023 for a given input voltage range of 0 - 4Vdc. This ADC number
shows up on the "PA Reject Service" screen on the GUI. For a detailed PA Module
and Cabinet phasing procedure refer to "5.4 PA Module Phasing" on page 5-5.
Figure 4-12 PA Module and Cabinet Phasing Screen
To access press: OUTPUT, OUTPUT SERVICE, PA REJ SERVICE
Detected rf sample
level, 0000 - 1023
PA Module Phase
Control Voltage
0000 - 1023
GOAL: To get the
detected rf sample
level readings
below 0030 (with
Gain set to LOW)
Module Group
select buttons
Reject Loads