Unisys Corporation

Robert V Jones

Dennis Carl Pulsipher

Roger W Call

John W Zscheile, Jr

Richard J Saggio

A novel vector quantization encoding system comprises a conventional vector formatter and a novel gross quantizer. The vector formatter generates vectors to be searched in a full code book of vectors. The gross quantizer generates pointers indicative of subsets of vector indices. The vector indices are indicative of groups of vectors to be searched in the full code book that are substantially less in number than the number of vectors in the full code book. A search controller is employed to search only the subset of vectors in the full code book and produce as an output the index of the one vector in the full code book closest to the formatted vector being searched so that the quality of a full code book searched is made faster without degradation of a full code book search.

Method and apparatus for increasing the speed of a full code book search

Apparatus and method are provided for adaptively modulating or combining a first signal with a second signal. A series of values of the first signal are taken and sequentially stored in a shift register. The maximum absolute value of the oldest N values (where N is an integer) stored in the shift register is then determined. Before, during or after that determination, the maximum absolute value of the remaining (newer) series of values of the shift register is also determined. The lesser of those two maximum absolute values is then determined. This lesser maximum absolute value is then multiplied by a gain factor representing the desired gain to produce a scale factor. The gain factor can be a preset constant, or can be based on the steady-state ratio of the power of the second signal to the power of the first signal. The second signal is then multiplied by the scale factor to produce a scaled signal. Meanwhile, the first signal has been delayed by an amount representative of the total time duration of the first N values in the shift register, or of the total time needed to obtain those first N values, or of the duration of the portion of the signal represented by those first N values. Considering the two peaks separately, combined with using this delay, in effect enables the resulting amplitude tracking to consider prospective as well as past values of the first signal. The scaled signal is then added to the delayed first signal. The amplitude of the scaled second signal thereby tracks the amplitude of the corresponding portion of the first signal, so that the scaled second signal cannot be readily detected unaided during any relatively low amplitude portion of the first signal.

Apparatus and method for amplitude tracking

A novel code division multiple access (CDMA) system and apparatus is provided which permits a plurality of encoded modulated data messages to be transmitted simultaneously on the same channel in one frequency band as a composite CDMA signal. An identification signal is generated and spread by a spreading signal having a duty cycle less than fifty percent to produce a combined signal which is transmitted to a receiver having a tapped delay with a plurality of taps each of which produce a replica of the received combined signal delayed by an odd multiple of the duty cycle of the spreading signal. Each of the replica signals is multiplied by a predetermined weighted value to produce weighted delayed signals and a controller responsive to the received combined signal, is employed for controlling individual weighted delayed signals which are then combined to suppress the spreading signal leaving the identification signal.

Apparatus and method for signal identification

An apparatus for detecting the presence of a target in an n-dimensional array of digital data samples comprises: 1) a reading module, which reads the samples from the data array in overlapping groups; 2) a quantizing module, coupled to the reading module, which quantizes each of the overlapping groups of data samples and which generates an index that identifies the quantized group; and 3) a comparing module, coupled to the quantizing module, which compares indexes from the quantizing module to multiple reference indexes, each of which represents a quantized group of data samples that identify a distinctive feature of the target.

Target recognition using quantization indexes

Apparatus is provided for compressing unfocused synthetic aperture radar (SAR) phase history pixel data by coupling the complex inphase phase history data output from the SAR to a first converter/compressor which produces compressed scalar log amplitude data and scalar phase pixel data. The output from the first converter/compressor is applied to a series to parallel converting means for converting plural scaler pixel data into vector data representative of a plurality of pixels. The output of the series to parallel conversion means is coupled to a second converter/compressor for converting the plural scalar pixel data into compressed encoded data representative of a plurality of pixels of unfocused SAR phase history data which is transmitted as compressed unfocused phase history data.

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Bountiful, UT, United States of America

Robert V Jones