The use of ASICs in the implementation of distance measurement using pulsed infra-red techniques

The defence group (DG) of THORN EMI electronics specializes in the design and manufacture of equipment for installation in guided weapon (GW) systems. These items of equipment often have to be installed in confined, peculiarly shaped spaces, such as the nose cone of a missile or shell, in order to be able to accommodate requirements for increased circuit complexity within the limited space envelopes available, DG has adopted increasing levels of system and circuit integration. These include the use of application specific integrated circuit (ASIC) technology and advanced manufacturing techniques, such as the use of surface mount components. Since the early 1970s, DG has developed a number of products, including altimeters and GW proximity fuzes, that embody distance measuring sensors based on pulsed infra-red techniques, using solid state, uncooled laser and photo-detector components. This paper reviews the evolution within DG of the electronic circuitry for this class of product. In particular, the merits of employing an ASIC implementation for major functional elements of the receiver signal processing chain are reviewed