Abstract: Fabry-Perot spectrometer comprises a Fabry-Perot etalon, a pair of cylindrical lenses with parallel vertices which lenses are spaced so that they smear light from a source in a direction which is perpendicular to their vertices, a focusing lens assembly, and a detector at the focus of the focusing lens assembly. The detector lens assembly comprises two cylindrical lenses, one with a vertex parallel to the vertex of the smearing cylindrical lenses and one with a vertex perpendicular to the vertex of the smearing cylindrical lenses in order to avoid spectral aliasing. The result is that light from "slices" on the source extending perpendicular to the smearing cylindrical lens vertices is smeared at the detector so that spectral information which would otherwise be hidden by virtue of interference maximums not falling on imaged emitting points appear on the smeared slices.

Abstract: The present invention provides a method for distinguishing a boundary of an object, and the object itself, from its background. In the method electromagnetic radiation is detected from at least two fields of view substantially spanning the boundary of the object and background adjacent to the boundary and superimposed or overlaid as images onto a detector. The method includes correlating spatial transitions in intensity of the overlaid images on the detector with a boundary of the object. When used for determining the attitude of a satellite with respect to the earth, the detector is a thermal infrared detector thereby providing a sharp contrast between the thermal emission of the earth and cold space. The invention provides a simple, effective method and device for determining satellite orientation and/or attitude with respect to a thermal infrared-emitting target body.

Abstract: A simplified fast maximum likelihood decoder for (1-D) channels comprising a first stage decoder for detecting possible charge violations in a threshold decoded input signal, a second stage decoder for resolving charge violations detected in the first stage decoder by finding the most likely data pattern consistent with the charge constraint of the input signal, and an output shift register for generating corrected estimated decoded data in response to receiving control signals output from the second stage decoder.

Abstract: A parallel sync circuit comprising a serial-to parallel converter for converting an input serial into a corresponding parallel signal, a phase detector for detecting possible phase of a sync word in the parallel signal and generating a phase signal responsive thereto, a sync word generator for receiving the phase signal and in response generating a phase shifted stored version of the sync word, and a correlator for comparing the parallel signal to the phase shifted stored version of the sync word and in the event of substantial identity therebetween generating an output signal for indicating detection of the sync word.