Her Majesty the Queen in Right of Canada, As Represented by the Minister of National Defence

Francois J Paquet

Joseph S Seregelyi

Shyam M Khanna

Rene G Apps

Disclosed is a D/A converter including a DC processing circuit, an analog switching device, a bootstrap circuit, and a third order low-pass filter. The boots trap circuit substantially reduces loading created by the low-pass filter circuit and acting on the switching device. Cross-over discontinuities in the continuous analog signal are reduced by interposing between each two successive pulses a cross-over correction pulse having opposite polarity and a predetermined fixed pulse-width. The D/A converter provides fast and accurate response over a long period of time.

Highly accurate digital to analog converter

A hybrid remote-sensing apparatus is based on an active high-power microwave (HPM) illuminator and a passive infrared (IR) detector for the detection of shallow buried landmines. A 2.45 GHz, 5 kW microwave source is used for illumination and the thermal signature at the soil surface is detected in the 8-12 &mgr;m region both in near real-time as well as after a brief time-delay following illumination. The thermal signature at the soil surface is primarily made up of two components. A thermal signature occurs at the soil surface in near real-time due to the interference of the incident beam and the beam reflected by buried mines. A second thermal signature is generated when temperature contrasts due to differential microwave absorption by a mine and the surrounding soil are conducted upwards from that mine location to the surface. Both signatures are dependent on the complex dielectric constants of mines and the soil. These signatures can be used to determine the location of different types of metallic and non-metallic mine surrogates, dummy mines without explosives and live mines with explosives.

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Nepean, Canada

Francois J Paquet