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Enterprise Control System

COFDM Downlink Equipment

COFDM Base Station System

Coded Orthogonal Frequency Division Multiplexing (COFDM) is a state of the art transmission technique using multiple carriers to provide high quality real time images. COFDM is able to operate in environments where conventional video links would fail through multipath interference. Using 1704 carriers in 8 MHz, the COFDM Standard Definition (SD) Base Station System has been optimised for surveillance and air-to-ground use.

COFDM Base Station System
Language version of AUDS video
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  • General Description
  • Technical Data

General Description

The Enterprise Control System Ltd (ECS) Standard Definition (SD) COFDM Diversity Base Station System consists of an Antenna Control Unit (ACU), an Active Multi Switched-Sector Antenna (MSA), a single omnidirectional antenna, a Video Link Digital Receiver (VLDR) and a Low Noise Block downconverter (LNB).
The ACU is used to control the MSA and interface with the VLDR. The addition of an optional second omnidirectional antenna provides diversity operation and a 6 - 8 dB link budget improvement over a single antenna equivalent system. Global Positioning System (GPS) information is multiplexed into the transport stream of the ECS COFDM transmitter and then decoded within the VLDR. This GPS information is then used to control the MSA. The output of both antennas is down converted to UHF band allowing IF cable lengths of up to 100 metres.
The VLDR has dual PAL, RGB, Y/C and MPEG2 transport stream video outputs. A GPS output is provided for Graphical Information System (GIS) display of transmitter GPS information.
The ACU can be fitted with its own GPS antenna allowing the Base Station System to be used for mobile or temporary applications.
The 1.4, 2.3 and 3.5 GHz ACU variant controls a 5 sector MSA. The 4.5 and 5.3 ACU variant controls a 6 sector MSA.

Technical Data

Antenna Control Unit specification

GPS Display: Alt, Lat, Long, Heading of transmitter
Elev, Dir and Range from antenna to transmitter
Antenna Display: Antenna selected, auto/manual, channel selected
Control: Sector auto/manual selection, sector selection, channel up/down, mains on/off
Antenna Data: 6-pin KPTC2E-10-6P-D-M
Power Supply: 240 VAC or 12 VDC with automatic switch over
Weight: 2.1 kg
Video Link Diversity Receiver specification
Sensitivity: -95 dBm typ (when used with ECS active antenna)
Channel Bandwidth: 8 MHz
Video Channels: Up to 2 simultaneously at full frame rate
Channels: Pre-selectable frequency channels (16 max)
Liquid Crystal Display: RSSI, channel selected, transmitter status and encryption identification
Light Emitting Diodes: OFDM lock, FEC lock and packet error
Size and Weight: 1U x 19’’ , 3.6 kg
Video Outputs: NTSC, CVBS, Y/C and MPEG2 transport stream
Decryption: Automatic and with RS232 input enabling remote control of decryption code
Power Supply: 240 VAC or 12 VDC with automatic switch over.