Abstract: A digital selective call receiver is modified to enhance the address decoding capability by providing access to received data, bit and frame synchronization signals, and a detect input terminal of an annunciator. A selectively attachable additional independent address decoding device including additional memory and an independent address decoder operating in parallel with the decoder in the selective call receiver is attached to the receiver for accessing the various signals and providing a detect signal to the annunicator when an additional independent address is decoded.

Abstract: A communication receiver is disclosed which can turn itself on or off depending upon the time of day. When the receiver is on, normal battery saving is performed. A time of day clock generates a time signal which is compared to predetermined turn on and turn off times. The turn on and turn off times may be permanently stored in memory or may be manually programmed at the receiver or may be received by the receiver and stored in a reprogrammable memory.

Abstract: An electronic device having a display is disclosed which comprises contacts for electrically coupling the display to the circuitry of the electronic device, and a mounting arrangement for removable attachment of the display to the electronic device, such that the display may be removed from the electronic device to be read. The electronic device may be a radio transceiver, and the display may be adapted to display a paging message from a paging receiver associated therewith.

Abstract: Certain present antenna assemblies require that their antenna structure be first rotated to a predetermined azimuth orientation prior to being retracted translationally along an axis to a stowed state so that it may conform to the surface of the antenna supporting structure which it is designed to rest against. An antenna assembly which requires no such prior maneuvering of the antenna structure before retraction thereof is disclosed. Retraction of the antenna structure in accordance with the present invention may occur at any random azimuth orientation of the antenna structure. In one embodiment, at least one cam follower bearing is fixedly coupled to a support housing of the antenna assembly and positioned to engage one of a plurality of integral cam grooves disposed on the surface of a shaft which supports the antenna structure and used to extend and retract the antenna structure with respect to the support housing surface.

Abstract: A new protective relay for determining the occurrence of a single-phase-to-ground fault and tripping the appropriate circuit breaker. At local and remote terminals of a protected line segment, three signals representative of an electrical parameter on each phase conductor are input to a local and remote protective relay. In both the local and remote protective relays, the three electrical parameter signals are manipulated to produce two evaluation signals. The two local evaluation signals produced in the local protective relay are transmitted to the remote protective relay, and the two remote evaluation signals produced in the remote protective relay are transmitted to the local protective relay. In the local protective relay the two local evaluation signals are manipulated to produce a third local evaluation signal, and the two remote evaluation signals are manipulated to produce a third remote evaluation signal.

Abstract: An apparatus and method for detecting a single-phase-to-ground fault on a three-phase electrical power system and for identifying the faulted phase conductor. Each phase conductor is monitored by evaluating three phasor signals associated therewith, i.e., the zero sequence current of the electrical power system, the negative sequence voltage on the phase conductor rotated 90 electrical degrees counterclockwise (or the negative sequence current on the phase conductor), and the quadrature phase voltage for the phase conductor rotated 30 electrical degrees counterclockwise. The coincidence of these three signals for a predetermined time indicates the occurrence of a single-phase-to-ground fault on the monitored phase conductor.

Abstract: A method of analyzing the doppler spectrum obtained from narrow band doppler filtering in the post-detection processing of a radar for the purposes of counting multiple targets moving in close proximity to one another is disclosed. More specifically, a set of contiguous doppler frequency signals is selected from the computed doppler frequency spectrum of a range gate of a radar look for establishing the target count thereof. The selected doppler frequency signals are processed in two passes with each pass including the steps of searching, threshold detection, and target counting. A pass count is established for each pass. The pass counts are combined in a predetermined count algorithm to establish a final count of the range gate being processed. Moreover, a selected group of contiguous range gates may be selected to establish a cumulative or total final count of targets in a selected portion of the range of a radar look.

Abstract: New logic circuitry for a directional comparison blocking protective relay scheme. A forward-reaching and a reverse-reaching protective relay located at the local and remote terminals of a protected line segment determine whether a fault is internal or external to the protected line segment. To carry out this function, the protective relays produce signals representative of fault location and communicate with each other via a communications channel. A fault detector and logic circuitry is provided at each terminal for processing the produced signals to determine the fault location and avoid tripping when the fault character changes. By using fault detectors to determine the existence of a fault, the logic at each terminal for combining the signals is simplified and security against false tripping is improved.

Abstract: A nonlinear noise-blanking circuit with memory. An information signal corrupted by a noise signal is input to the nonlinear noise-blanking circuit. The information signal is blanked during noise impulses and an estimate for the blanked information signal is inserted therein. Various embodiments of the invention disclose means for determining an appropriate estimate. For example, the estimate can be a simple positive or negative dc value corresponding to the sign of the information signal prior to noise corruption. Alternatively the first and second derivatives of the information signal prior to noise corruption can be used to generate an expected future trajectory of the information signal, and this value inserted in the information signal during the blanked interval. Also, a sample and hold circuit can be used to "remember" the value of the information signal prior to the inception of a noise impulse. This "remembered" value is then inserted in the information signal during the blanked interval.