User manual

GENERAL DESCRIPTION
The MVS mobile radio is a synthesized, wideband radio,
utilizing microcomputer technology to provide high reliability,
high quality, and high performance in two-way, FM, mobile
communications. The MVS provides 25 watts of RF output
power across each band split (403-440 MHz, 440-470 MHz,
and 470-512 MHz) without retuning. The receiver can cover
any 20 MHz segment of each band split without retuning.
The MVS radio is easy to operate with large buttons for
function selection and an easily viewed liquid crystal display
(LCD). The control panel and the LCD are backlighted for
night operation.
All radio functions are stored in a programmable electri-
cally erasable PROM (EEPROM). Channel selection, volume
setting, scan channels, and scan on-off function are all perma-
nently remembered even when the 12V battery is disconnected.
Seven interchangeable control panels are available for up-
grading and adding options to the radio. The plug in control
panel modules can provide 2 channels, 16 or 128 channels with
scan, Type 99 decoding, and Public Address.
The radio is normally mounted in a conventional configura-
tion with the entire unit under the dash or in a DIN size open-
ing inside the dash. A remote mount option allows controlling
the main radio assembly remotely from the Front Cap Assem-
bly.
The receiver is able to scan on both noise squelch operation
and Channel Guard (tone or digital). The scan rate is fast, re-
quiring only I5ms per channel (66 channels/second). A 16
channel radio will scan the priority channels ever 90ms (11
times/sec) and the non-priority channels every 330ms (3
times/sec). The scan time will be faster when fewer channels
are programmed into the scan memory.
The microphone is equipped with a Channel Guard hook-
switch which disables Channel Guard whenever the micro-
phone is removed from its holder.
The radio is programmed using an IBM compatible per-
sonal computer equipped with a RS-232 serial interface con-
nector. A EGE supplied RS-232 interface box and cable are
also required. The computer can program or reprogram the
customer frequencies, Channel Guard, carrier control timer,
and other programmable customer options. Programming is
done through the microphone jack without opening the radio.
A temperature compensated oscillator module provides
±0.0005% (5 PPM) oscillator stability. An optional ±0.00025%
(2.5 PPM) high stability oscillator is available.
The MVS radio consists of the following assemblies:
• RF Board
• PA Board
• Audio Board
• Logic Board
• System Board
• Front Cap Assembly
The boards are all mounted onto a main casting assembly
with easy access to each for servicing. Interconnect plugs and
ribbon cables are used to interconnect the boards eliminating
problems with pinched wires when replacing covers.
RF BOARD
The RF Board includes the synthesizer, the transmitter, and
the receiver circuits.
Synthesizer Circuit
The synthesizer generates all transmit and receive RF fre-
quencies. The synthesizer frequency is controlled by the micro-
processor located on the Logic Board. Frequency stability is
maintained by a temperature compensated reference oscillator
module. Transmit audio, which is processed on the Audio
Board, feeds the synthesizer to modulate the VCO. The VCO
output frequency is doubled and drives both the transmitter ex-
citer and the receiver mixer.
Transmitter Circuit
The transmitter consists of a fixed-tuned exciter module, a
PA module, a power control circuit, a PIN diode antenna
switch, and a low pass filter.
The PA module is capable of 10 Watts output to drive the
PA Board. The power control circuit controls the PA module by
sampling the PA Board output to maintain constant output
power across the band.
The RF output level is internally adjustable for rated power.
A thermistor in the control protects the PA from overheating.
Receiver Circuit
The dual conversion receiver circuit consists of a front end
section, 45 MHz first IF, a 455 kHz second IF, and a FM detec-
tor. All audio processing and squelch functions are accom-
plished on the Audio Board.
PA BOARD
The PA Board amplifies the RF Board PA module output
to the rated output of 25 Watts. The 25 Watt output is fed
back to the RF Board where the power control circuit, the
antenna switch, and the low pass filter are located.
AUDIO BOARD
The Audio Board provides all audio and tone processing
for the receiver and transmitter, except the receiver volume
control and 3 watt audio PA. The board also contains the in-
ternally adjustable receiver squelch circuit. The Audio Board
obtains all control signals from the Logic Board.
LOGIC BOARD
The Logic Board contains the microprocessor and asso-
ciated memory circuits which include an EPROM for con-
trolling the processor and a programmable "personality"
electrically erasable PROM (EEPROM) to store customer
frequencies, tones, and options. The microprocessor pro-
vides tone generation and detection, frequency data to the
synthesizer, and sends and receives data to another micro-
processor in the front cap assembly for the LCD display and
the control panel commands.
SYSTEM BOARD
The System Board controls the main input power to the
radio. The front panel POWER switch and the IGNITION
SENSE input lead provide the necessary signals to the
MOSFET switching circuit.
The board also interfaces all option connections from the
internal boards in the radio with the optional items outside of
the radio. All options that apply to the radio, interconnect to
the System Board through the back of the radio using an op-
tional cable.
FRONT CAP ASSEMBLY
The Front Cap Assembly contains the Control Board,
Control Panel, LCD Assembly, and houses the internal
speaker.
The Control Board contains a microprocessor which in-
terfaces the control panel keyboard and a LCD module to
two serial data lines for communication with the main radio
microprocessor on the Logic Board. The Control Board also
contains a digital volume control and a 3 watt audio power
amplifier.
EQUIPMENT AND FEATURES
MICROPHONE
The standard mobile combinations use a transistorized
dynamic microphone with an internal Channel Guard hook-
switch. The microphone is housed in a sturdy case, and the
extendable coiled cord plugs into a jack on the bottom of the
radio. The microphone is secured to the radio by a cable
clamp. A magnetic microphone hanger is supplied with the
microphone. The Channel Guard is disabled when the mi-
crophone is removed from the magnetic hanger allowing the
operator to monitor the channel before sending a message.
Optional DTMF and desk microphones are available.
CARRIER CONTROL TIMER (CCT)
The Carrier Control Timer turns off the transmitter after
the microphone push-to-talk (PTT) switch has been keyed
for a pre-programmed time period. A pulsing alert tone will
warn the operator to unkey and then rekey the PTT to con-
tinue the transmission. The timer can be programmed to time
out for 30 seconds to 7.5 minutes in 30 second increments.
The timer can be enabled or disabled for each channel.
CHANNEL GUARD
Channel Guard provides a means of restricting calls to
specific radios through the use of a continuous tone coded
squelch system (CTCSS) or a continuous digital coded
squelch system (CDCSS). Tone frequencies range from 67.0
Hz to 210.7 Hz in 0.1 Hz steps. There are 83 standard pro-
grammable digital codes. The Channel Guard tone frequen-
cies and codes are software programmable. Both tone
frequencies and digital codes may be mixed on each chan-
nel. These codes and frequencies are listed in Table 1.
SQUELCH TAIL ELIMINATION (STE)
STE is used with tone and digital Channel Guard to
eliminate squelch tails. The STE burst is transmitted when
the microphone PTT is released. The receiving radio de-
codes the burst and mutes the receiver audio for 250ms. This
mute time allows the transmission to end and to mute the
squelch tail. The radio looks for STE on the received signal
when the microphone is either on or off hook. The STE is
enabled for transmit and/or receive by PC programming the
radio’s personality.
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