U.S. Philips Corporation

Andrew I Cox

Andrew A Turnbull

A thermal radiation detection apparatus has an array of pyroelectric detector devices (10) for receiving radiation from a scene whose outputs, e.g. from associated source followers (12) are supplied via a multiplexer (14) in turn to a processing circuit (20) which is responsive to each detector device signal to produce an output which substantially faithfully reproduces the received radiation signal without requiring that a chopper be used. The processing circuit operates with a correction factor to produce an output signal with first and second components proportional respectively to the device signal and its rate of change, the relative proportions of the components being in a ratio according to the device's thermal time constant. Initial device voltage level and the device's electrical time constant effects can be corrected by additional processing in the circuit (20), producing a third component of the output proportional to the integral of the device's output and in a ratio to the first component according to the electrical time constant.

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Reigate, United Kingdom

Andrew I Cox