Scan converter makes military systems bus-independent

Suppliers of display systems are continually being asked to provide more flexibility and higher performance in systems at a lower unit cost. As a result, the use of commercial off-the-shelf (COTS) products is becoming more prevalent. But the use of COTS products can introduce problems for the system developer. Support for some defense contracts must be provided for 25 years, far longer than required in the commercial environment.

Apr 1st, 1997

Scan converter makes military systems bus-independent

Suppliers of display systems are continually being asked to provide more flexibility and higher performance in systems at a lower unit cost. As a result, the use of commercial off-the-shelf (COTS) products is becoming more prevalent. But the use of COTS products can introduce problems for the system developer. Support for some defense contracts must be provided for 25 years, far longer than required in the commercial environment.

To overcome this problem, OEMs are developing products that can be made both computer- and bus-independent. In the Calisto multifunction consoles, which form part of the combat management system for the Charles de Gaulle aircraft carrier, systems developer CS-Defense (Toulon, France) is using COTS products with dual-screen Hewlett-Packard workstations to display scan-converted radar and video.

At the heart of the system is a VME-based radar scan converter from Primagraphics (Cambridge, England). A video keyer is used to combine the high-resolution RGB signal generated by the scan converter with the display output from the workstation. By using video keying to interface directly with RGB video, only the control software residing on the host workstation or PC must be recompiled.

Because the images are combined at the video output, they do not generate any additional load on the workstation`s internal bus or graphics hardware. Only control information needs to be passed between the processing subsystem and the workstation, and this can be performed using a variety of interfaces, including low-bandwidth serial connections.

"This split in functionality simplifies system integration and subsequent upgrading of the workstation and allows non-real-time display protocols such as X and Windows-NT to be used for the display of real-time processed data," says Nick Porter, support engineer at Primagraphics. For more information send a message to njp@primag.co.uk.

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