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Home - SecurityWood & Douglas Ltd is dedicated to providing reliable, secure and flexible radio link systems to law enforcement and military bodies. The work undertaken for these applications is also suited to security networks.
We welcome interest in our bespoke and generic designs but must emphasise that products with a military or security application are exclusively supplied to bone fide organisations.
DVMO (Digital Video for Moving Objects) is a high quality video link specifically designed for law enforcement and military applications.
The dVMo digital video link allows video, audio and data signals to be carried via radio for both fixed and mobile applications. The prime benefit of the dVMo equipment is the ability to deliver high quality video images from moving objects or in situations where buildings and obstructions would make transmission difficult.
DVMo has been in production for over 4 years and is proven in operational use.
Technical Introduction - A detailed and technical introduction to DVMO
Systems Overview - Explanation of COFDM and international standards for transmission
DVB-T - Description of Digital Video Broadcasting (DVB)
Diversity Reception - Multiple paths and reflective path solutions for moving signals
Diversity Antenna System - Diagram showing a Diversity Antenna System model.
dVMo - RDT - Transmitter
dVMo - TP - Portable Transmitter
dVMo-T - Integrated encoder/transmitter
dVMo-TM - Portable Transmitter Pack
dVMo-TML - Portable Transmitter Pack
A range of RF Power Amplifiers is available to increase the range and noise immunity of the system by increasing the power output of the dVMo-T. Although the power (1W, 5W or 10W from the dVMo-PA1, PA5 and PA10 respectively) is relatively low compared to analogue systems, the range is much greater than would normally be expected because of the advanced transmission system. Because of the needs of this system, the amplifiers are extremely linear and conservatively rated.
The amplifiers are simple to use, needing a suitable power supply and connection between the dVMo-T and antenna. Several versions are available to suit different requirements for power supply, monitoring, mounting etc.
dVMo-PRE, dVMo-DCV and dVMo-uDCV DVMo masthead units are designed to be mounted as close to the antenna as possible. They all amplify the signal before the downlead to the dVMo receiver, but the down converters (dVMo-DCV and dVMo-uDCV) also translate signals received in the SHF region (e.g. 2.5GHz) down into the UHF band, because downlead losses would be unacceptable at these frequencies. Thus both units obtain the best signal-to-noise ratio. Phantom powering allows standard co-ax downlead to be used with no additional power wiring.
The dVMo-uDCV is a dual unit, whereas two of the dVMo-DCV or dVMo-PRE are required for diversity working.
dVMo- IP adaptors - TCP/IP and UDP transmission.
dVMo-MXD - Transport Stream Decoder
dVMo-MXE - Transport Stream Encoder
