Specifications

Section K
Analog To Digital Converter
K.1 Introduction
This section describes the Analog to DigitalConverter board, and
includes Function, Location, Block Diagram Description, trou-
bleshooting information and oscilloscope plots of key points.
NOTE: Parts List for this board is in Section VII.
K.2 Function
The Analog to Digital Converter board converts the (Audio +
DC) signal from the Analog Input board into a Digital Audio
Signal.
The Digital Audio Signal determines how many RF Amplifiers
are to be turned on at any instant, via the Modulation Encoders.
Conversion functions, conversion fault logic, and data latches are
included to accommodate these functions. Big Step Sync and
Reconstructed Audio signals, for use in other sections of the
transmitter, are also generated by circuits on this board.
K.3 Location
The Analog to Digital board is located in the center control
compartment (SEE VIEW 13).
K.4 Block Diagram Description
K.4.1 RF Flow
An A/D Sample Pulse that is processed on the Driver Encoder is
applied to a Buffer amplifier. The output frequency of the Buffer
Amplifier is at the carrier frequency or 1/2 the carrier frequency
depending upon the transmitter frequency. The output of the
Figure K-1. Analog To Digital Converter Block Diagram
888-2339-002 K-1
WARNING: Disconnect primary power prior to servicing.