Abstract: A digital synchronizer examines a signal transmitted at a predetermined baud rate for a predetermined time. Upon completion of the predetermined time, a decision is made as to whether or not the signal included the predetermined baud rate. If the signal includes the predetermined baud rate, a bit clock is established indicative of the boundaries and center of each baud symbol. The synchronizer samples the signal at a multiple of the baud rate and accumulates the phase relationship between the samples and transitions of the signal during the predetermined time. Upon conclusion of the predetermined time, the distribution of the phase relationships is examined and the presence or absence of signal is determined. If the presence is determined, the bit clock is established.

Abstract: A portable receiver has a time of day clock and receives a signal indicative of the location of the portable receiver. The portable receiver has a memory which has a plurality of locations with corresponding time zones. Upon reception of the location signal, the receiver determines the time zone of the location and the time zone of the time of day clock. The time of day clock is then adjusted to correspond to the time zone of the location. The location signal may also be used to adjust the operating frequency of the receiver.

Abstract: A paging receiver receives a message signal having an address field and a data field. The message has at least one address within the address field and a plurality of packets in the data field. The data packets contain a predetermined amount of information. A method for conserving power during reception of a message signal having an address field comprising a number of addresses involves entering the power conserving mode of operation after attempting to correlate a predetermined number of addresses with the paging receiver's address, where the predetermined number is less than the number of addresses in the address field. In addition, message information may be included within a plurality of packets by several methods including placing a corresponding plurality of addresses in the address field, each address indicating the occurrence of message information, or by indicating in one packet that information follows in a subsequent packet.

Abstract: An apparatus (112) for charging a plurality of batteries, having at least one aperture (300) capable of receiving a plurality of batteries therethrough, and including at least two slots (110.sub.I and 110.sub.I+1) for accommodating the plurality of batteries therein during a charging process. The apparatus (112) charges the plurality of batteries, and collectively rotates the slots (110.sub.I and 110.sub.I+1) so as to position a slot (110.sub.I) accommodating at least one charged battery with an aperture (400) to facilitate the removal of a charged battery. Optionally, a date coding machine (130) applies a representation of a calendar date to the charged batteries.

Abstract: Messages received by a selective call receiver are stored in source files with a user allocated number of message storage slots in response to a message source signal indicating the source of the message. Messages are retrieved utilizing the source files facilitating message location in large memories. Source files are retrieved on a priority basis which is a function of a predetermined priority associated with each source file and the status of messages stored therein.

Abstract: A selective call receiver allows reprogramming of the options stored within a code plug only after entry of a correct password. After a predetermined number of unsuccessful attempts to enter a correct password, the selective call receiver is user disabled such that the user may not reenable the selective call receiver without returning the receiver to the manufacturer or without replacing expensive components thereof.

Abstract: A paging receiver has a synthesizer for governing the receive frequency. The paging receiving further has characteristics which are varied in response to the receive frequency. These characteristics include varying the bandwidth of a loop filter within a phase lock loop within the synthesizer as well as varying the time in which a detector circuit used to extract a DC level from a recovered audio signal is disabled. Furthermore, the bandwidth of the loop filter is varied in response to switching from a first receive frequency to a second receive frequency in order to provide for either a uniform frequency lock time or for a rapid frequency lock time. Furthermore, the time in which the detector circuit is disabled is correspondingly changed.

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 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 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 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 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: Known LCD devices of the type having an upper polarizer (36), a liquid crystal cell (28), a lower polarizer (38) and a reflector (42) and working using ambient light to provide illumination lose contrast because the light passes twice through both polarizers. By providing a layer of light concentrating plastic (44) between the upper polarizer (36) and the LCD cell (28), light emitted from bevelled edges (48) of an aperture (46) in the plastic is directed towards the cell and reflector directly, without passing through the upper polarizer (36). This is in addition to the normal ambient light passing through the front polarizer. This increases the intensity of light reaching the observer (20) and thus the contrast of the display.

Abstract: A selective call receiver includes a message reminder alert controlled by a reminder switch and independent of the receipt of subsequent messages.

Abstract: A receiver receives a transmitted digital signal having a synchronization signal and information signals. The receiver synchronizes to the synchronization signal and detects predetermined signals within the information signals. When it is determined that an information signal is substantially different from the predetermined signals, power is conserved for the remainder of the information signal.

Abstract: An apparatus is described for the dual modulus prescaling of a high frequency signal. The apparatus comprises a dual modulus divider, second divider, synchronization circuit for providing a first modulus control signal to the dual modulus divider, and means for coupling the output of the second divider to the input of the synchronization circuit when a second modulus control signal is in a first state.

Abstract: A driving circuit including a single transformer drives a piezoelectric transducer and an electroluminescent lamp. The circuit is coupled to the driving circuit for limiting the peak current through the transformer.