Abstract: A housing (100), that is suitable for use in a automated manufacturing and/or testing environment, is constructed and arranged to substantially enclose and shield a trimmable electrical circuit (107) from radio frequency interference external to the housing (100). At least a portion of the housing (100) is constructed and arranged to shield while contemporaneously allowing a laser beam (114) to pass therethrough so as to focus on at least a portion of the trimmable electrical circuit (107) and thereby laser trim the trimmable electrical circuit (107).

Abstract: Receivers synchronize to signals sequentially transmitted from several transmitters prior to receiving signals simulcast by the transmitters. The relative delay differential of the received sequential signals is measured and used to determine the optimal sampling positions for the simulcast signals.

Abstract: A bipolar return-to-zero signal received from a communication channel (302) is sampled (402) to provide signal information that is processed (FIG. 5) to determine signal variation information. In accordance with this signal variation information, at least one operational parameter of an equalization system (400) is varied.

Abstract: A voltage multiplier selectively couples an input voltage potential (10) from a voltage source (Vin) to an energy storage device (22) in response to a first control circuit (18). A second switching circuit (26) is used to selectively serially couple the first energy storage device (22) and the voltage source (10) to provide an intermediate voltage potential (Vin), which is selectively coupled to a second energy storage device (30) in response to a second control signal (28') that is provided by a second control circuit (38) coupled to the intermediate voltage potential (Vim). The output of the second energy storage device (30) comprises an output voltage potential (Vout) being greater than the input voltage potential (Vin).

Abstract: A paging terminal is provided for storing incoming pages during terminal downtime and subsequent transmission thereof.

Abstract: A communication system has an information signal having a plurality of data streams. The data streams are simultaneously modulated on a multi-level symbol transmission. The data streams may have either independent or dependent signalling protocols. A transmitting device generates the information in one of several embodiments. A first receiver receives the information signal and process only a first data stream for messages. A second receiver receives the information signal and process only the second data stream for meassages. A third receiver is capable of selectively receiving and processing a plurality of data streams. The third receiver is shown in several embodiments for selecting the data streams.

Abstract: A paging receiver receiving message information having one of a plurality of (BCH) code word structures has a programmable error correcting apparatus for correcting bit errors within the message information. The programmable error correcting apparatus may be configured in response to identifying a signalling system and the code word structure corresponding to ther signalling system, or in response to changes in the code word structure within the message. A simplified error correcting apparatus may correct a single bit error within a code word structure. The programamble error correcting apparatus is capable of correcting any two bit error combination within the code word structure and contains sequential and combinational logic circuits. The programmable error correcting apparatus is integrated together with a microprocessor on a monolithic integrated circuit.

Abstract: A baud rate detector determines the baud rates of signals received by a selective call receiver. If the signals have no detectable baud rate or the baud rate of the received signals does not match that of a plurality of known selective call network transmission baud rates, the selective call receiver indicates to its user that it is out of range of the network's transmitters.

Abstract: An electronic device includes a printed circuit board for mounting electronic components thereon. An antenna, such as a dual loop antenna, is secured to the printed circuit board and acts as a bezel to mount a display, such as a liquid crystal display, onto the printed circuit board. A lens cap through which the display may be viewed is positioned over the display and is detachably coupled to the antenna for securing the display to the antenna/bezel.

Abstract: A light guide is optically coupled to a light source and engagingly positioned between a liquid crystal display and a printed circuit board for both damping vibrations from and backlighting the liquid crystal display.

Abstract: A method and apparatus selectively rebroadcasts information received from a first selective call network system by a second selective call network system. A selective call receiver monitors the messages broadcast by the first selective call network system and, when no messages comprising the preamble code of the selective call receiver are received, the selective call receiver will, from time to time, monitor the messages transmitted by the second selective call network, including the messages rebroadcast from the first selective call network system.

Abstract: A single purpose robot arm end effector having a ring shaped frame positioned around the periphery thereof with a plurality of extendable drivers mounted in the frame for movement between a nonfunctioning position and an operative position. Each of said drivers can be tooled up for unique or dedicated applications so that the arm will be performing many different functions during most of a manufacturing cycle, instead of only performing one function for a short period of time during the manufacturing cycle.

Abstract: A simulcast system is provided which includes a primary transmitting station surrounded by first and second rings of secondary or simulcast transmitting stations. Communication links are provided to link the primary transmitting station with the secondary stations. Respecting time delay circuits are provided in the links such that the secondary stations retransmit the information signal from the respective links at substantially the same time as the primary information signal from the primary transmitter arrives at the respective secondary transmitter.

Abstract: A pager (1) includes switches (12,13,14,15) for setting the priority of a message expected to be received at a predetermined time on a substantially continuous carrier signal. A receiver (3) is then activated for a period of time determined by the priority setting prior to the expected time of the message. The length of the period of time is greater for a higher priority setting so that if the carrier signal is not detected, an alert is indicated either visually (9) or audibly (10) giving the user time to place himself into range of the carrier signal. Furthermore, the pager (1) may operate in a reduced power mode prior to the predetermined time.

Abstract: A battery capacity indicator is described which measures the battery terminal voltage at two discharge rates, monitoring the resultant differential battery voltage at predetermined time intervals, and comparing the resultant differential battery voltage to a set of predetermined differential battery voltages which are stored within a memory within the battery powered device. Each of the predetermined differential battery voltages corresponds to one of a set of predetermined battery capacities for each type of battery used in the device. The battery capacity indicator provides to the user a continuous display of the available battery capacity.

Abstract: A DC-DC converter regulates the maximum current through an inductor. The DC-DC converter operates within a paging receiver and boosts a voltage from a single cell battery to substantially 3.1 VDC in order to operate circuits which require more voltage than that produced by the single cell battery. Such circuits include CMOS microcomputers and code plug. The DC-DC converter is current regulated thus providing for improved power conversion efficiency. The DC-DC converter is active when the voltage is below a minimum voltage and inactive when above a maximum voltage. The DC-DC converter provides for a wide range of load currents from the converted voltage without being controlled by a microcomputer and while delivering the power to the loads with an improved efficiency.

Abstract: A paging receiver is operative to receive and accept a call signal including a receiver characterization portion which is decoded by the paging receiver to govern processing operations, characterized by the characterization portion, in regard to call signals corresponding to specified assigned call addresses of the paging receiver. In one embodiment, the receiver characterization portion of a call signal includes at least one characterization code and corresponding memory location code for storage of the characterization code in a memory of the paging receiver. Each memory location code corresponds to an assigned call address code of the paging receiver.

Abstract: A battery saver type paging receiver includes an improved peak and valley amplitude detection type data limiter section with mode control operation thereof, digital word storage of acquired peak and valley amplitude values, and self tuning capabilities. More specifically, the data limiter section includes a controller for controlling the peak and valley detection circuits to acquire respective peak and valley amplitude values in digital word form in a first operational mode and to hold the peak and valley amplitude digital words in corresponding storage registers in a second operational mode. The controller may transfer the data limiter section into a third operational mode during which the peak and valley digital words may be altered a predetermined count to effect a self-tuning thereof. In one embodiment, the third mode of operation is effected during the transfer between the second and first modes of operation.

Abstract: A piezo-electric resonant vibrator is described comprising a resonant armature having a centrally located weight, and at least four planar circular spring members which provide a restoring force normal to the movement of the weighted armature within a non-magnetic housing which encloses and supports the armature. A piezo-electric driver is coupled to the armature for inducing movement of the armature at a predetermined resonant frequency. A ferromagnetic plate is mounted to the housing and magnetically couples to a magnet which is coupled to the weight to maintain tension on the armature when an excitation signal is not supplied to the piezo-electric driver, and the armature is at equilibrium.