Glenayre Electronics Inc. GL-T8311SA Manual Do Utilizador
GL-T8xx1 Transmitter System
Glenayre Document Number: 9110.00166
THEORY OF OPERATION
Revision K: 08/30/99
Page: 6-6
Copyright © 1999 Glenayre
The metering board compares the AGC REF signal (J6-3) from the exciter and the FWD
PWR dc reference signal (J1-6) from the PA RF compartment. The metering board attempts
to hold power constant by using these signals to generate the AGC voltage (J1-19) which
it sends to the PA RF compartment. All stages, except the first IPA stage, are under the
influence of the AGC signal.
PWR dc reference signal (J1-6) from the PA RF compartment. The metering board attempts
to hold power constant by using these signals to generate the AGC voltage (J1-19) which
it sends to the PA RF compartment. All stages, except the first IPA stage, are under the
influence of the AGC signal.
6.1.2.3
Signal Measurement and Alarm Gathering
Refer to Table 4-7, Detail of J1 Connections (DB-25) between Metering Board and PA RF
Compartment. Each PA board and IPA board have separate, fused supplies, whose currents
are measured by A/D converters which are multiplexed to the A/D1 line (J6-1) and A/D2
line (J6-9) to the exciter. The exciter has three input-select lines which determine the circuit
to be measured. Refer to Table 6-1, Input-Select Metering Lines from Exciter.
Compartment. Each PA board and IPA board have separate, fused supplies, whose currents
are measured by A/D converters which are multiplexed to the A/D1 line (J6-1) and A/D2
line (J6-9) to the exciter. The exciter has three input-select lines which determine the circuit
to be measured. Refer to Table 6-1, Input-Select Metering Lines from Exciter.
Several metering points may not be used depending on the metering board assembly and
the transmitter it is in. The labels of the measured parameters appear on the VDT screen
when it is used to measure operating parameters. Refer to the VDT manual for details.
the transmitter it is in. The labels of the measured parameters appear on the VDT screen
when it is used to measure operating parameters. Refer to the VDT manual for details.
6.1.2.4
PA Fault
On nearly all versions of the metering board, no hardware circuit for PA-fault detection is
installed, and PA faults are determined by software, as power supply voltage, PA currents,
and RF power output can be read by the software.
installed, and PA faults are determined by software, as power supply voltage, PA currents,
and RF power output can be read by the software.
On a few versions of the metering board, there is a hardware fault-detection circuit. If any
of the PAs experiences a fuse-blowing fault, the PA FAULT line (J6-11) becomes active
(HI).
of the PAs experiences a fuse-blowing fault, the PA FAULT line (J6-11) becomes active
(HI).
Table 6-1 Input-Select Metering Lines from Exciter
input-select line
J6-x pin
1
13
2
6
3
14