Controller Theory Of Operation; Radio Power Distribution - Motorola VHF2 Service Information

2-8
5.0

Controller Theory of Operation

This section provides a detailed theory of operation for the radio and its components. The main
radio is a single-board design, consisting of the transmitter, receiver, and controller circuits. A
control head is connected by an extension cable. The control head contains LED indicators, a
microphone connector, buttons, and speaker.
In addition to the power cable and antenna cable, an accessory cable can be attached to a
connector on the rear of the radio. The accessory cable enables you to connect accessories to the
radio, such as an external speaker, emergency switch, foot-operated PTT, and ignition sensing, etc.
To Synthesizer
16.8 MHz
Reference Clock
from Synthesizer
Disc Audio
To RF Section
5.1

Radio Power Distribution

Voltage distribution is provided by five separate devices:
U514 P-cH FET - Batt + (Ext_SWB+)
U501 LM2941T - 9.3V
U503 LP2951CM - 5V
U508 MC 33269DTRK - 3.3V
U510 LP2986ILDX - 3.3V Digital
Mod
Out
ASFIC_CMP
SPI
Digital
Architecture
3.3V
Regulator
Figure 2-5 Controller Block Diagram
Audio/Signaling
Architecture
.
Audio
PA
µP Clock
RAM
HC11FL0
EEPROM
FLASH
THEORY OF OPERATION
External
Microphone
Handset
Internal
Microphone
External
Speaker
Internal
Speaker
SCI to
Accessory &
Control Head
Connector