User Manual
SECTION 1: THEORY OF OPERATION
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General Block Diagram
General Block Diagram Definitions
The standard IP circuit board contains ten (10) sections defined below.
Input/Output Circuitry associated with the radio’s DB9 data connector providing all the
RS232 data and handshake functions, including the necessary level
changes.
Microcontroller Manages the operation of the radio loading the selected transmit/receive
frequencies into the injection synthesizer, controls the operation of the
modem, and determines which receiver provides a better signal from a
given transmission. Also provides transmit time-out protection in the event
a fault causes the radio to halt in the transmit mode.
Transmit Modulation Circuitry that amplifies the analog audio signal from the modem and uses it
to modulate the voltage controlled oscillator (VCO) and 10 MHz reference
oscillator in the injection synthesizer section. Modulating the VCO and
reference oscillator simultaneously results in a higher quality FM signal.
Modem Converts serial data into an analog audio waveform for transmission and
analog audio from the receiver to serial data. Serial data appears on the
radio’s RS232 port, which connects a Mobile Data Computer (MDC) or a
Voice Interface Unit (VIU).
The modem supports a 115.2 Kbps data transmission rate on the serial
port, SLIP protocol, and up to 19.2 Kbps over-the-air rate. Within a single
chip it provides forward error detection and correction, bit interleaving for
more robust data communications, and third generation collision detection
and correction capabilities.
Injection Synthesizer Provides programmable, ultra stable signals for the radio. One synthesizer
incorporates phase lock loop technology used for both receiving and
transmitting.
Input /
Output
D
D
A
A
T
T
A
A
Micro-
Controller
Injection
Synthesizer
Transmitter
Transmit
Processin
g
Baseband
Routin
g
Receiver 1
Receiver 2 Modem