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Summation Research continues its history
of advanced communications processors with the MD-4040
GMSK Digital Modem. Designed for integration with a variety
of RF transceivers, the MD-4040 provides cost effective
network communications capability for licensed and non-licensed
narrow-band data
applications.
The MD-4040 utilizes advanced transmission processing
and protocols resulting in a very reliable and flexible
solution for SCADA networks, telemetry,
data link transceivers, and other wireless data applications.
The unit handles all of the data communications management
tasks providing a robust, reliable link. Problems such
as multi-path, fading, interference, intermodulation, and
other issues that commonly corrupt links are overcome using
our powerful RF-LinkNet protocol. The MD-4040 is capable
of detecting and transparently correcting these common
errors
that can
corrupt data links.
The MD-4040 also provides sophisticated networking capabilities
such as data broadcast and radio addressability. Each unit
can serve as a repeater, allowing wide coverage areas and
mesh networking capabilities.
The units meet the FCC narrow-band re-farming requirements
and feature:
Data rates up to 9.6
kbps. Our unique over-the-air protocol, RF-LinkNet
allows for advanced error detection and packet retransmission
with a minimum
of overhead. On-board buffering is provided for smooth
information flow.
Multi-point Addressability:
Each unit is individually addressable, supporting over
65,000
unique IDs. Networks of MD-4040 based radios provide for
individual, multicast/group, or broadcast transmissions
for point-to-point, point-to-multipoint, or full mesh operation.
When desired, this capability can be reduced to 255 unique
IDs in order to minimize networking message overhead.
Error Detection and Correction:
When so configured, the advanced RF-LinkNet protocol used
by MD-4040 Modems detects collisions and other situations
causing errors in the transmitted data and resolves these
errors through optional packet retransmission.
Reliable, Bandwidth Efficient
Operation:
Data is received exactly as it it transmitted, without
dribble or missing header bits. Our over-the-air
protocol provides configurable error detection and retransmissions
required for reliable operation. Based on unique customer
requirements, these features can be tailored to minimize
network overhead and collision probabilities while still
providing the necessary robust operation of all communications
links.
Store-and-Forward Repeating:
Each unit can be programmed to automatically forward packets
to one or more other modems
that may be out of range of the originating station. Networks
of MD-4040 based radios use this capability to fill in
blind-spots and extend the coverage area. Any given station
can operate as a single node, a repeater node, or both
simultaneously
for added network design flexibility.
Extended Range Operation:
Embedded error-correction and retransmission capabilities
of the MD-4040 extend the range for reliable data communications
paths. Our Store-and-Forward feature can increase operating
ranges even further by relaying messages from station to
station. Furthermore, multiple relay modems can be configured
for any given path to extend the operation well beyond
that supported by more typical network devices.
Radio Control: The MD-4040 provides a control interface
for typical RF transceivers for programming and operational
control, keying, and carrier detect.
Auto-Transmit and Receive: Modems automatically manage
the flow of information for simulated full-duplex operation.
The transmitter is automatically keyed whenever the appropriate
amount of data is ready to be transmitted.
Static or Dynamic Addressing:
Radios can be set for point to point and/or message relay
operation for transparent serial or packet data. Packetized
data can include addressing information for message routing.
Network Health and Status:
Optional network diagnostic capabilities provides the means
to dynamically and bi-directionally test any given point
to point interface link. In addition to basic self-test
health information of the modems involved, link performance
data is also provided indicating received signal strength
and bit-error detections at both ends of the communications
path.
The MD-4040 can be provided with a matching RF Transceiver
for UHF or VHF Land Mobile operation.
Specifications:
| Modulation |
GMSK
Modulation Index: 0.5 BT
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| Data Rate |
9600 baud
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| Performance |
Link Performance - < 10E-4 BER at 12 dB SNR in 25 KHz channel
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| Throughput Delay |
The first byte
of a transmitted message is output from the receiver
within 10 msec
after the programmable delay period
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| Data Interface |
Signal Types – RS-232
Protocols – Asynchronous, DCE
Data Rates – 1200, 2400, 4800, 9600, and 14400
Signals - TXD, RXD, RTS, CTS, and GND
Format – 8 bit characters, E/O/N parity, 1 or 2 stop bits
Configuration – Data rate, parity, and stop bits set via configuration
commands to the modem card
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| Radio Interface |
TX Audio – +/- 125 mVDC centered at 1.65 VDC
corresponding to – to + 5 KHz respectively
RX Audio – +/- 125 mV corresponding to + to – 5 KHz respectively
PTT– TTL signal to put radio in TX mode (programmable sense)
CD – TTL signal indicating RX carrier presence (programmable sense)
Power – unregulated DC power pass through (35 mA RX and 300 mA TX at +12
VDC and 2 Watt output)
Ground
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| TX Baseband Signal |
Can be calibrated for each radio
Calibrated settings include peak to peak level and DC offset
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| Data Processing |
Rate buffering – 1K byte TX/RX buffers
Data packetizing – Acquisition preamble/frame sync insertion
Selectable MessageProtocol modes:
Burst mode - variable length from 1 to 255 bytes
Transparent mode – any length message
Data scrambling to improve minimum data transition density
Selectable Network Protocol modes:
Disabled, Point to Point, Point to Multi-Point, Broadcast
Error Detection with Optional Message Retry
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| Programmable Parameters |
Delay from CTS to PTT (0 to 255 msec)
Delay from PTT to Data Transmission (0 to 255 msec)
Transmit Audio Scaling Factor (0.0 to 1.0 in 0.0039
increments)
Transmit Audio Offset Control (0 to +/- 125 mVDC
in ~61 uVDC increments)
Transmit Push to Talk Active High or Low
Data Interface Baud/Parity/Stop Bit Selections
Receive Audio Waveform Invert or Not Invert
Receive Carrier Detect Processing Enable or Disable
Receive Carrier Detect Active High or Low
Receive Acquisition Sensitivity Threshold
Receive Termination Guard Time (0 to 255 msec)
Receive Error Detection Enable or Disable
Maximum Retransmit Count and Backoff Time Increment
Message Protocol Transparent or Burst Packet
8 or 16 Bit Network Addressing
Dynamic or Static Addressing
Relay Operation Enable or Disable with Relay Site Addresses
Relay Unique ID for Multiple Repeater Operation
Data Scrambling Enable or Disable
Programmable Data Pattern for Transmitter Calibration
All programmable parameters stored in non-volatile memory
to serve as power up default configuration
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| Input Power |
+10 to +14 VDC (unregulated)
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| Power Consumption |
< 200 mA
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| Packaging |
Board size – 3.0 x 2.0 x 0.625 inches L
x W x H
Connectors:
- Power and Data I/F: 13 pin terminal block
- Radio I/F: 9 pin terminal block
Indicators – green LED’s – right angle mount from board
edge
- Power – illuminated when 12 VDC is present on board
- RX Sync
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TX Data
Board includes mounting holes compatible with common
UHF/VHF transceivers
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