Motorola LBI-38653 - Manual (Page 3)

INTRODUCTION
The Ericsson GE Conventional MDS Radio is a rugged
two-way FM mobile radio which operates in the 440-470
MHz and 470-512 MHz frequency bands. The MDS is a wide
band synthesized radio utilizing microcomputer technology to
provide reliable high quality simplex two-way mobile commu-
nications. Its transmitter output power level is 40 watts over
the wide bandwidth of each split. The receiver has an allow-
able 12 MHz maximum receive channel separation. There are
two versions available for each split, a 2-channel and an 8-
channel. The basic radio package includes the following fea-
tures:
•
Microprocessor Control
•
Synthesized RF Channel selection (frequency control)
•
7-Segment LED Channel Display
•
Multi-tone Channel Guard (CTCSS) Encode/Decode
•
Multi-code Digital Channel Guard (DCG) Encode/De-
code
•
Automatic Hook Switch Channel guard Disable
•
Channel Activity Sensing (CAS)
•
Carrier Control Timer (CCT)
•
±
5 ppm frequency stability
•
Talkaround, radio to radio direct Communication
•
Type 99 Tone Decode
•
Field Programmable with PC
•
Fixed Squelch, threshold programmable
•
Internal 4-watt Speaker, with volume control
•
Front Mounted Microphone Connector
•
Rear Mounted Antenna TNC Connector
•
Rear entry power connections
•
ANI Encode
The small size of the MDS radio makes it ideal for front
mounting in conventional vehicles. The radio is operated with a
simple hand held microphone in combination with the following
operating controls, all located on the front panel.
•
Power ON/OFF Switch
•
Channel UP/DOWN Selector
•
Volume UP/DOWN Control
•
Monitor Switch for Channel Guard Disable
•
Type 99 Tone RESET Switch, to reset the tone decoder.
Refer to the Operator’s Manual LBI-38651 for a complete
description of the operating procedures.
RADIO DESCRIPTION
MAIN BOARD ASSEMBLY
A sturdy aluminum casting houses the Main Board Assem-
b ly (N2 9 /8 5 1 54 0 0 12 20 f or th e 4 40 -4 70 MHz b and
N29/85154001250 for the 470-512 MHz band). There is com-
plete accessibility to the Main Board with the radio’s top and
bottom covers removed. The Main Board contains the following
circuits:
•
Microprocessor and associated Logic
•
Frequency Synthesizer
•
Transmitter Exciter
•
Receiver
•
Audio Processing (for both transmit and receive paths)
•
Tone and Squelch Processing (for both transmit and
receive paths)
•
Voltage Regulators
Logic Circuitry
The radio’s logic circuitry includes the 80C535 microproc-
essor with associated EPROM and Electrically Erasable PROM
(EEPROM) memory and latch circuitry. The Microprocessor
controls the functions of the transmitter, the receiver, the inputs
from the operator and the outputs to the operator.
Synthesizer
A programmable Synthesizer generates both transmit and
receive operating frequencies. It includes a synthesizer chip, a
dual modulus counter, a temperature compensated reference
oscillator (TCXO) and a voltage controlled oscillator (VCO); all
part of an operating phase lock loop, with its requisite loop filter.
Transmitter
The radio transmitter includes the Synthesizer’s modulated
VCO and the fixed tuned exciter amplifiers. The exciter ampli-
fiers are wideband, covering both splits in the UHF band without
retuning. The exciter output is fed to the Power Amplifier Board
through a coax cable. The exciter provides 35 dB of gain to drive
the Power Amplifier with 3 watts. The transmitter output level
at the antenna connector is factory set for a rated output power
of 40 watts. The power control circuit detects the power output
of the Power Amplifier. Using the error signal, the power control
circuit varies the DC supply voltage to the first stage of the
exciter. This will hold the transmitter output level constant.
SPECIFICATIONS (Cont.)
Spurious Emissions
Radiated Meets FCC requirements
Conducted -57 dBm maximum
RX Spurious Response 70 dB minimum
Adj Ch(2-Sig) Selectivity -70 dB max @ 25 kHz (EIA)
Intermodulation Attenuation -70 dB minimum
RX Modulation Acceptance
±
7 kHz minimum
Audio Distortion 2% maximum @ 0.5 Watt (EIA)
10% maximum @ 4 Watts and 1 kHz
Audio Frequency Response Within +2, -8 or a 6 dB/octave de-emphases,
300-3000 Hz (EIA)
RX Hum and Noise
Unsquelched -45 dB maximum
Squelched -70 dB maximum
Audio Output Power 4 watts, @ < 10% Distortion
Speaker Impedance 4 ohms
MDS RADIO PACKAGE NUMBERS
MDS RADIO PACKAGE NUMBERS
PACKAGE NUMBER DESCRIPTION
TLU22 UHF MID-SPLIT 2 CHANNEL, 40 WATT
TLU28 UHF MID-SPLIT 8 CHANNEL, 40 WATT
TLU32 UHF HI-SPLIT 2 CHANNEL, 40 WATT
TLU38 UHF HI-SPLIT 8 CHANNEL, 40 WATT
OPTIONS
OPTION NUMBER DESCRIPTION
MC3G DESK TOP MIC
AN1R 1/4 WAVE, ROOF MT ANTENNA W/TNC CONNECTOR
ZM3L EXTERNAL WEATHERPROOF SPEAKER AND CABLE
LS1F MIL SPEC SPEAKER, 4 OHMS, 5 x 5
CD1E SPEAKER CABLE
PD1A NOISE FILTER KIT
SU1C ALARM RELAY KIT
EC1A DOC POWER SET
MA1L DESK TOP RADIO MOUNTING WEDGE
PS1D 240 VAC-12 VDC, 13A 50/60 Hz Power Supply
PS5K 120 VAC-12 VDC, 13A 50/60 Hz Power Supply
LBI-38653 LBI-38653
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