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GNS 400W Series Maintenance Manual
Page 4-55
190-00356-05
Rev. A
TESTS
AGC
The course deviation measured through G/S SERIAL_OUT must be 0 ddm
±
.0091ddm when
using the glideslope centering test signal as the RF level is varied between -76 to -33 dBm (this is
an optional test).
The course deviation measured through G/S SERIAL_OUT must be 0.091
±
.0091 ddm when
using the standard glideslope deviation test signal as the RF level is varied between -76 dBm to -
33 dBm.
Selectivity (Bandwidth)
The course deviation measured through G/S SERIAL_OUT must be 0
±
.0091 ddm when using
the glideslope centering test signal at -87 dBm as the RF frequency is varied
±
17 kHz from the
assigned channel.
Deflection Error: At frequencies displaced by
±
17 kHz from the assigned channel frequency, a -
87 dBm 0.091 ddm standard glideslope signal must produce a dbar output voltage of 78
±
10 mV.
Nose Bandwidth: The input signal level required to produce the reference AGC voltage must not
vary more than 6 dB over the input signal frequency range of
±
17 kHz from the assigned channel
frequency.
Skirt Bandwidth: At frequencies displaced by
±
132 kHz on either side of the assigned channel
frequency, the input signal level required to produce reference AGC voltage must be at least 60
dB, respectively, greater than the level required to produce reference AGC voltage at the assigned
channel frequency (this is an optional test).
Deflection Balance
The standard deflection at -56 dBm with the 90 Hz greater than 150 Hz, and the standard
deflection with the 150 Hz greater than 90 Hz must be within
±
0.00728 ddm and opposite
polarity as tested in hot and cold environments, and must be within
±
0.005 ddm and opposite
polarity as tested at ambient when measured through G/S SERIAL_OUT.
The standard deflection at -56 dBm with the 90 Hz greater than 150 Hz, and the standard
deflection with the 150 Hz greater than 90 Hz must be within
±
6.24 mV and opposite polarity as
tested in hot and cold environments, and must be within
±
5 mV and opposite polarity as tested at
ambient when measured through G/S + UP.
Glideslope Course Deviation Flag Requirements
Requirement: the glideslope course deviation flag must be flagged when measured through G/S
SERIAL_OUT:
When the RF level of a standard deviation test signal produces 50% or less of standard deflection
of the deviation indicator:
•
In the absence of 150 Hz modulation.
