User's Manual

Digital UHF Transmitter Chapter 4, Circuit Descriptions
DT835A, Rev. 1 4-25
The (A13) Front Panel Meter is for
Combined Output Power that is
controlled by (S1) the Meter Control
Switch, the (A15) Front Panel Meter is
for Side A Output Power with (S2) the
Meter Control Switch and the (A17)
Front Panel Meter is for Side B Output
Power with (S3) the Meter Control
Switch.
4.5.1 (A4, A5, A6 & A11) Splitter
Board (1181-1002; Appendix D)
The (A4) Splitter Board (1181-1002)
takes the ALC reference from the (A4)
Variable Phase/Gain Tray at J1-1 and
splits it six ways that connect to the
UHF Amplifier Trays mounted in the
Side A Amplifier Array.
The (A5) Splitter Board (1181-1002)
takes the ALC reference from the (A5)
Variable Phase/Gain Tray at J1-1 and
splits it six ways that connect to the
UHF Amplifier Trays mounted in the
Side B Amplifier Array.
The (A6) Splitter Board takes the
Combined Reflected Sample Input at
J1-1 and splits it. One of the split
Combined Samples connects to the
front panel Meter, one is used for
Remote Monitoring and the other two
connect back to the UHF Exciters for
use in the VSWR Cutback circuitry.
The (A11) Splitter Board (1181-1002)
takes the Combined Aural Sample
Input at J1-1 from the (A10)
Visual/Aural Metering Board and splits
it. One of the split Aural Samples
connects to the front panel Meter and
the other is used for Remote
Monitoring.
4.5.2 (A10) Visual/Aural Metering
Board (1265-1309; Appendix D)
This board was originally designed for
Analog operation only. When used in a
digital transmitter the visual references
and circuits become combined and the
aural references and circuits are not
used.
The (A10) Visual/Aural Metering Board
has a Combined Forward Sample from
the Output Coupler Assembly of the
Transmitter connected to J1 on the
Board where it is split. One Forward
Sample connects to J2 on the board
that is cabled to J9, the Transmitter
Output Sample Jack, located on the
front panel of the Metering Panel. The
Combined Forward Sample on the
Visual/Aural Metering Board is split
again with one Sample used to produce
a Combined Forward Sample, that
connects to the front panel Meter (A13)
and also to the rear panel for Remote
monitoring. The other Combined
Forward Sample produces a combined
Aural Sample that connects to the
(A11) Splitter Board.
4.5.3 (A7, A8 & A9) Dual Peak
Detectors (1159965; Appendix D)
The (A7) Dual Peak Detector takes the
Combined Reflected Sample Input from
the Output Coupler Module and splits it.
A peak detected output of the reflected
sample connects to the (A6) Splitter
Board. The (A7) Dual Peak Detector
also has a Reject Sample Input from
the Reject Output Coupler Module and
splits it. One of the peak detected split
Reject Samples connects to the front
panel Meter and the other is used for
Remote Monitoring.
The (A8) Dual Peak Detector Module
takes a Reflected Sample from the Side
B Amplifier Array that is peak detected
and connected to the (A17) front panel
meter. Another input to the (A8) Dual
Peak Detector Module is a Forward
Sample from the Side B Amplifier Array
that is peak detected and connected to
the (A17) front panel meter.
The (A9) Dual Peak Detector Module
receives the Reflected Sample from the
Side A Amplifier Array which is peak
detected and connected to the (A15)