Abstract: An integrated circuit chip carrier (100) provides an improved mounting pad density. The chip carrier (100) includes a flexible substrate (102) with pads (104) on the top surface for interconnection with an attached integrated circuit chip (302). The chip carrier (100) further includes a mounting pad array (502) on the bottom surface having an interconnection with the pads (104), and a rigid substrate (202) having an array of holes (204) extending through it. The top surface of the rigid substrate (202) is fixedly attached to the bottom surface of the flexible substrate (102). Individual holes of the array of holes (204) correspond to and align with individual pads of the mounting pad array (502). The chip carrier (100) further includes solder (206) disposed on the mounting pad array (502) and extending through the array of holes (204) beyond the bottom surface of the rigid substrate (202) for mounting the integrated circuit chip carrier (100) to a circuit bearing substrate (700).

Abstract: A messaging system capable of transmitting messages to receivers which roam between coverage areas. In one configuration, a coverage area (100) is divided into a plurality of zones (110). A single simulcast system identification (SSID) number is assigned which consists of a local identification number which identifies the coverage area (100), a zone identifier which identifies a zone (110) within the coverage area, traffic splitting flags and a frequency. For larger roaming areas, a network (200) is defined as consisting of a plurality of service areas (210) and is identified by network roaming identification information (NRI). NRI information and/or SSID information is stored in a receiver according to desired coverage and like information is transmitted in the corresponding zone or service area.

Abstract: In each receiver (40) at least one datecode is stored which defines a subscription period during which the receiver is entitled to display received messages. For each message (200) to be transmitted, a datecode which defines a particular subscription date to be associated with the message is generated, the datecode defined by a predetermined number of bits. The datecode is compressed into a compressed datecode (220) based on the datecode, the compressed datecode being less in number of bits than the predetermined number of bits of the corresponding datecode. A modified checksum word (230) for the message is generated based on the plurality of bits which represent the message (200) and the predetermined number of bits which represent the datecode that corresponds to the compressed datecode (220). The modified checksum word (230) is associated with the message and the compressed datecode (220) for transmission.

Abstract: An oscillator circuit (143) comprises a master phase-locked loop (PLL) circuit (202) that receives as input a first reference frequency signal (136) and generates a first clock signal (210) in response to an oscillator control signal (212). The oscillator circuit (143) includes a frequency sensitive slave circuit (206) having at least one frequency sensitive element (322) that is responsive to a tracking control signal (214) to generate a second clock signal (216). A tracking control circuit (204) is responsive to the oscillator control signal (212) for generating the tracking control signal (214). The tracking control signal (214) serves as a bias signal, and is connected to the frequency sensitive slave circuit (206) for achieving a fast power up sequence of the oscillator circuit (143).

Abstract: Network roaming information (NRI), which comprises identifies a network (200) and a service area (210) within the network (200), a receiver address, is transmitted in a network (200) during a predetermined number of time slots of a signal, whereby the signal is transmitted in consecutive cycles, each cycle comprising a plurality of consecutive time slots. The placement of the NRI in the transmitted signal is made to be predicted by a receiver so that the receiver can compute an expected time slot location of a NRI to be compared with a stored NRI. The placement of the NRI is made according to an algebraic relationship between moduloN of the transmission frequency of the signal, moduloN of the order of the cycle, and moduloN of a portion of the NRI, wherein N is an integer.

Abstract: A zero-intermediate frequency receiver circuit (11) for receiving a radio frequency signal detected by an antenna (14). The receiver circuit (10) comprises a second local oscillator circuit (25) and an oscillator circuit (60) of a phase locked loop demodulator (36) which are identical and track each other so as to provide a more accurate reference for processing a demodulated signal. A current reference (39) providing a current reference signal utilized by the second local oscillator circuit (25) and the oscillator circuit (60) of the phase locked loop demodulator (36).

Abstract: A phase locked loop (PLL) circuit for use as a demodulator and other applications. The PLL circuit (200) comprises a phase detector (210), a transconductance amplifier (212) and a current controlled oscillator (ICO) (214). The phase detector has two signal inputs and two outputs, and detects a phase difference between signals at its inputs. A capacitor C1 is connected to the output of phase detector (210) and develops an output voltage signal vo(t). A transconductance amplifier (212) is coupled to the capacitor C1 and converts the output voltage signal vo(t) to an output current signal. The ICO (214) is coupled to the transconductance amplifier (212) and the second output of the phase detector (210) and generates an output signal having a frequency which is proportional to an input current signal. The output signal of the ICO (214) is coupled to the second signal input of the phase detector (212).

Abstract: A messaging system and method capable of transmitting group messages throughout a Network (200) such that receivers which are outside of a "local" or "home" area of coverage receive such group messages, whereas receivers which are in a "local" area of coverage over ride and do not receive the group message as a result of decoding system identifiers and ignoring those messages having network roaming identification.

Abstract: A method of interconnecting circuit modules (30) to mother boards (50) each having a plurality of mating solder pads (32, 52) is available. The solder pads (32, 52) have respective pairs of arms (40, 42) and (54, 56) with a venting channel (36, 58) formed between each pair of arms to vent solder medium when the solder pads are reflowed to interconnect the circuit modules and mother boards.

Abstract: A fax selective call receiver system (10) featuring compression of a fax message with an optimal one of a plurality of compression code-books (50). At least a portion (44) of a source document (26) is compressed with each of a plurality of code-books (50) and the smallest resulting data file is selected as the optimal compressed file. The compressed data file is transmitted to a selective call receiver (40) together with an index identifying the optimal code-book. The selective call receiver (40) stores each of the plurality of code-books and accesses the particular code-book for decompressing the data file on the basis of the received index. In an alternative embodiment, the fax message is divided into composing segments (SI1, SI2 and SI3) and each segment is compressed with each code-book to determine the optimal code-book for each segment.

Abstract: A peak and valley measuring circuit (40) featuring a single digital-to-analog converter (DAC) (100), a peak counter (110), a valley counter (120), and a comparator (130). The peak and valley measuring circuit (40) uses the peak counter (110) when detecting peaks of the recovered audio signal and the valley counter (120) when detecting valleys of the recovered audio signal. The DAC (100) is used in conjunction with one of the counters (110) or (120) depending on whether peaks or valleys are being detected, and is preferably a current-mode DAC.

Abstract: A selective call receiver (111) receives a synchronous selective call signal (99) having synchronization portions (102 and 104) and a frame identification portion (106). Upon finding the signal the selective call receiver's bit and frame synchronizers (126 and 128) synchronize to a frame (100) of the signal and a frame ID decoder (130) decodes the frame ID (106). A comparator (136) compares the received frame ID (106) with an ID (142) assigned to the receiver, and optionally a first and second mask (134A and 134B) to determine the number of frames until an occurrence of a desired frame and conserves power until the occurrence of the desired frame (188).

Abstract: A time diversity communication system (150) comprises a messaging terminal (154), a queue (156) at the messaging terminal for queuing incoming messages, an encoder (158) for encoding a first fragment of a message and the remaining fragments of a message, a transmitter (160) for repeatedly transmitting the first fragment in a plurality of time slots to at least one selective call receiver (201) operating in a first mode, the number of time slots equaling a desired number of repeat transmissions and wherein the first fragment contains instructions for decoding the remaining fragments in a second mode by the selective call receiver, the transmitter (160) also repeatedly transmits the remaining portions of the message in subsequent time slots and at least one selective call receiver that decodes the first fragment and remaining fragments of the message in accordance with instructions in the decoded first fragment.

Abstract: A holster (201) serves to protect an information display (202) in a selective call receiver (200) from breakage due to an impact in an area proximate to the information display (202). When the selective call receiver (200) is retained in the holster (201) in a first orientation, a second portion (207) of the holster contiguously covers an opening in the housing where the information display (202) is positioned. The second portion (207) protects the information display by shunting energy from the impact into at least a front section (204) of the selective call receiver's housing and the holster (201).

Abstract: A system and method for minimizing current drain of a battery in a portable receiver, such as a selective call receiver (110), by monitoring the warm-up time of a component (130) of the receiver (116), such as an oscillator (134), to periodically determine changes in the warm-up time of the component (130). That component of the receiver is powered up prior to designated time slots (440) by a time period (Wt) according to the dynamic changes in receiver warm-up time.

Abstract: A tactile button (10) for activating a tact switch within electronic circuitry enclosed by a housing element (104). The housing element (104) comprises an arcuate edge (106) forming an arcuate aperture (108). On a first end (110) of the arcuate edge (106) is a first lug (112) having a circular aperture. On a second end (116) of the arcuate edge (106) is a second lug (114) having a parabolic aperture. The arcuate member (102) comprises a first shaft (122), disposed on a rear surface (120), for connecting to the circular aperture, and a second shaft (124), also disposed on the rear surface (120), for connecting to the parabolic aperture. The arcuate member (102) further comprises a stopper (126) for limiting the movement of the arcuate member (102) within the housing element (104) when hinged to the first lug (112) and the second lug (114).