Andrew D Duran

US Patent:

50362895, Jul 30, 1991

Filed:

Mar 17, 1989

Appl. No.:

7/326808

Inventors:

Andrew J. Duran - Stamford CT

Assignee:

Infrared Systems, Inc. - Orlando FL

International Classification:

H03K 522

US Classification:

328117

Abstract:

An infrared detector output of a radiometer is amplified and inverted to provide a first signal which is amplified to a predetermined level and a second signal which is inverted with respect to the first signal and amplified to a fraction of the predetermined level of the first signal. The first and second signals are alternately sampled to sample portions of those signals which occur when the detector of the radiometer is viewing the target and then viewing the reference. The signals are sampled once while the detector of the radiometer is looking at the target and twice occurring on each side of the target sample when the detector is looking at the reference signal. The first and second signals are separately integrated in accordance with a predetermined timing pattern determined by the sampling rate of the first (target) and second (reference) signals. The peak integrated outputs of the first and second signals are held then sampled to produce the demodulated output from the radiometer. The integrating circuit is then dumped during the time of the second target view of the detector, to restart the integrating cycles which permits integrating every other signal which appears on the detector through the radiation chopper of the radiometer.