User's Manual

Model 1150A DVOR
2-66 Rev. - November, 2008
This document contains proprietary information and such information may not be disclosed
to others for any purposes without written permission from SELEX Sistemi Integrati Inc.
Figure 2-25 Extender Board
2.3.2.22
Commutator Control CCA Theory
The Commutator Control CCA connects to a 25 conductor cable on the Control Backplane CCA. This cable
originates from one of the two Audio Generators in the Control rack. The output of the Commutator Control CCA
exits onto the backplane and to two 40-pin connectors that connect to ribbon cable from the Commutator CCAs. A
4-pin header on the Commutator Control CCA may be strapped to enable/disable automatic ground-check.
Capability for the ground performance check of the antennas and commutator switching is provided. This check is
automatic after is has been started by the technician and therefore is called an Automatic Ground Check system.
When started, the Monitor CCA sends a switch position code to the Commutator control CCA via the 25-pin cable
originating at the Control rack.
The switch positions start at 0 and increment by one until 15. Each position represents 22.5 degrees of antenna
rotation from the nominal position. At each position the Monitor CCA determines the azimuth angle at the Field
Monitor antenna location. From this data the errors are measured and a Fourier analysis is performed to generate the
display data.
The error as determined during the ground check is analyzed to determine the bias, the duantal error, quadrantal
error and octantal error. The bias error is the average error around the station. The duantal error is sinusoidal with a
rate of one cycle in the 360 degrees around the station. The quandrantal error is sinusoidal with a rate of four cycles
in the 360 degrees around the station. The octantal error is sinusoidal with a rate of four cycles in the 360 degrees
around the station