Motorola ASTRO XTS 5000 - VOCON Board; Figure 3-5. VOCON Board Block Diagram

6881094C28-D July 16, 2004
Basic Theory of Operation: VOCON Board 3-5
3.5 VOCON Board
The vocoder and controller (VOCON) board (See Figure 3-5) comprises the dual-core processor
(Patriot), which contains the radio’s microcontrol unit (MCU) and digital signal processor (DSP) in a
single integrated circuit (IC) package; its memory ICs; an audio and power supply IC (GCAP II); a
digital support IC (Flipper); and the audio power amplifier. Connected to the VOCON board are the
liquid-crystal display (LCD) board, transceiver board, keypad flex, controls/universal flex, and
(optional) encryption module.
Figure 3-5. VOCON Board Block Diagram
The microcontrol unit portion of the dual-core processor controls receive/transmit frequencies, power
levels, display, and other radio functions, using either direct logic control or serial communications
paths to the devices. The microcontrol unit executes a stored program located in the FLASH memory
device. Data is transferred to and from memory by the microcontrol unit data bus. The memory
location from which data is read, or to which data is written, is selected by the address lines. The
microcontrol unit requires a 16.8 MHz clock and a 32 kHz clock.
The DSP portion of the dual-core processor performs signaling and voice encoding and decoding, as
well as audio filtering and volume control. The DSP performs Private-Line/Digital Private-Line (PL/
DPL) encode and alert-tone generation. The DSP transmits pre-emphasis on analog signals, and
applies a low-pass (splatter) filter to all transmitted signals. The DSP controls squelch, deviation, and
executes receiver and transmitter filtering. The DSP executes a stored program located in the
FLASH memory device.
The DSP requires a 16.8 MHz clock. Additionally, the DSP requires clock and frame synchronization
from the Abacus III digital back-end IC on the transceiver board to generate another clock and frame
synchronization signal, and these signals are supplied to transmit DAC on the transceiver board.
The digital support IC is supplied with a 16.8 MHz clock from the transceiver board. Using this clock,
the digital support IC generates a 13 MHz clock for the audio and power supply IC. Additionally, the
digital support IC uses a crystal to generate the 32 kHz clock used by the dual-core processor and
audio and power supply IC.
SRAM
1MByte
INTERFACESUPPORT
ESDProtectionand
SideConnector
Circuitry
ASIC
ClocksandSide
ConnectorSupport
VOCON
Board
CONTROLLERANDMEMORY
FLASH
8MBytes
Dual-Core
Processor
MCUandDSP
Keypad
22pins
Display
22pins
Encryption
40pins
AUDIOANDPOWER
Audio
EEPOT
Pre-ampand
PowerAmp
GCAPII
andDiscrete
VoltageRegulators
RF
26pins
Universal
40pins
MAEPF-27413-A