United States of America As Represented by the Secretary of the Air Force

Honeywell G.m.b.h.

Alliant Techsystems Inc.

Ronald A Belt

Edward A Page

Frank E Bothwell

Randy A Doblar

J Brian Sharkey

Dale F Berndt

Gary David Havey

James D Joseph

Guy D Couturier

A security system for detecting a gunshot event. A communication link, and a number of pole units are arranged in a dense grid. Each one of the pole units includes a microphone and a signal conditioning and thresholding unit coupled to the microphone. The signal conditioning and thresholding unit outputs a detection signal in response to an event when an output signal from the microphone exceeds a peak background average. A data acquisition and signal processing unit is coupled to the signal conditioning and thresholding unit for discriminating gunshot events. The data acquisition and signal processing unit remains in a powered down stand-by mode so as to conserve energy until a detection signal is received. The data acquisition and signal processing unit includes apparatus for identifying a gunshot event by measuring an initial pulse time duration and subsequent pulse pattern features, and a communication interface coupled at an input to the data acquisition and signal processing unit. A central processor is coupled to the communication link so as to receive data from the pole units where the central processor and the pole units operate so as to detect and locate gunshot events sensed by one or more of the pole units.

System for effective control of urban environment security

A security system for detecting and reporting gunshot events for control of urban environment security which includes a communication link coupled to a plurality of pole units arranged in a dense grid. Each of the plurality of pole units includes a microphone, a data acquisition unit coupled to said microphone, a signal processor for discriminating gunshot events, and a communication interface apparatus coupled at an input to the signal processor. The communication interface also has an output coupled to the communication link, where the communication interface transmits and receives data on the communication link. A central processor is coupled to the communication link so as to receive data from and transmit data to the plurality of pole units. The central processor and the plurality of pole units operate so as to detect and locate gunshot events sensed by one or more of the plurality of pole units.

Pairs of cross coupled transistors are configured as a bistable regenerative circuit. Isolation means, such as diodes or transistors, are provided in the cross coupling paths to ensure that if the logic state of one transistor is temporarily changed by radiation striking the circuit, the logic state of the other transistor it is paired with will not change and the logic state of the unchanged transistor will be utilized to maintain the logic state of the other pair of transistors. CML, DTL and SDFL circuits are disclosed as the preferred embodiments.

Radiation hard gated feedback memory cell

Means and methods are provided for processing the quantity Si which corresponds to a point i in space where Si=(Xi.sup.2 +Yi.sup.2).sup.1/2 and Xi and Yi are quantities lying along mutually orthogonal axes in the space. Si is approximated by the expression A.vertline.Xi.vertline.+B.vertline.Yi.vertline. where A and B are constant coefficients selected to minimize the error in value of Si according to a selected error computation. A and B can be approximated as a binary power series with each series including a preselected number of terms. Another embodiment does not require means for approximating A and B as binary power series, but segments the coordinate space into m sectors and computes and Am and Bm for each of said m sectors. A particularly advantageous application of the invention is its use in a device and method for processing edge data concerning an edge in an optical image where Si is the Sobel, Prewitt or Roberts square root edge operators.

Means and method of processing optical image edge data

The device performs the function ##EQU1## for image processing, where W.sub.i are fixed weights for any specific application. It uses a PROM and accumulator algorithm, in which the memory stores the values ##EQU2## in 2.sup.M words, with addresses formed from one bit of each data word in a given bit position. In operation the most significant bit of each data word is used first to address memory, and in successive clock cycles the other bit positions are used down to the least significant. The memory output words are supplied to the adder-accumulator, and in each clock cycle the adder-accumulator output is shifted left one bit and used as a second input thereof. Then if the data words have N bits designated j=0 to N-1, after N clock cycles the memory output words have each been effectively multiplied by 2.sup.j and accumulated in the sum.

Programmable signal processing device

In a charge-coupled-device the registers of two adjacent arrays are interleaved in a novel serpentine structure to provide a refresh-cell width of four times the width of a single-shift register.

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Plymouth, MN, United States of America

Ronald A Belt