Abstract: A channel scanning communication receiver (204) operates in a system that transmits information in cycles (104) including subsequences (106). The receiver determines whether to operate in a scanning or locked mode by making (302) signal quality pass/fail decisions for subsequences transmitted in a predetermined group of cycles. A decision is made for a transmission of a subsequence, and subsequence active/inactive decisions are made (304) for the subsequences transmitted in the predetermined group of cycles, based upon the signal quality pass/fail decisions made for the subsequences. The receiver determines (306) whether the system is time-shared or continuous, based upon how many active decisions and inactive decisions are made, and selects (310, 312) the scanning or locked mode in accordance with predetermined rules for time-shared or continuous systems, according to whether the system is time-shared or continuous.

Abstract: A method and apparatus for DC-DC conversion. The apparatus includes a voltage detector (152) for detecting a voltage level in the circuit; a capacitive voltage doubler configuration of the DC to DC conversion circuits (130); a capacitive voltage tripler configuration of the DC to DC conversion circuits (130); selector circuitry (134) responsive to the voltage detector (152) for enabling the doubler or tripler configurations; and a voltage regulator (132) for regulating the converted DC voltages. The selector circuitry (134) initially enables the doubler, and then disables the doubler and enables the tripler when the voltage level drops below a reference voltage. In an alternate embodiment, high load signal HLVBB is provided when a high power load is to be enabled, such that the selector circuitry (134) temporarily disables the doubler and temporarily enables the tripler until the high load signal is inactive.

Abstract: A method and apparatus controls zone registrations in a radio communication system providing radio coverage to a portable subscriber unit (122, 1200) within a plurality of zones (402). A fixed portion (102) of the radio communication system cooperates with the portable subscriber unit (122, 1200) to adjust at least one registration variable in a memory of the portable subscriber unit (122, 1200) for moderating the zone registrations. The portable subscriber unit (122, 1200) then moderates the zone registrations to a limited number in accordance with the at least one registration variable.

Abstract: A communication receiver (100) utilizing a synthesizer (143) employs a discrete-time phase locked loop which includes a reference oscillator (135), a phase error detector (202), a discrete-time analog computing element (206), an integrator (210), a controlled frequency generator (211, 212), and a frequency divider (214). The discrete-time analog computing element implements a discrete-time analog lead-lag network circuit. This circuit includes a clock and logic circuit (216), at least one discrete-time analog queuing element (218), and an analog computing engine (222). The queuing element (218) includes N analog signal lines, N analog storage lines, N control lines, and N.sup.2 controllable switches. Each controllable switch is coupled between each of the N analog signal lines and each of the N analog storage lines. In addition, N charge storage elements are coupled between each of the N analog storage lines and a common circuit node.

Abstract: A method and apparatus improves a distribution of an underfill material (504) applied between a flip chip die (202) and a circuit board (310) at a flip chip site (302) having a solder mask (308). An aperture (304) is formed (806) in the solder mask (308) by removing a predetermined majority of the solder mask (308) from the circuit board (310) within the flip chip site (302) before mounting the flip chip die (202). Then the flip chip die (202) is mounted (810) to the flip chip site (302). The underfill material (504) is then applied (812, 814, 816) such that the underfill material (504) flows into the aperture (304), thus improving the distribution of the underfill material (504).

Abstract: A method and apparatus for mitigating effects of multipath fading, interference, and noise in a single sideband (SSB) signal transmitted by a radio communication system and demodulated by a portable subscriber unit (122) utilizing a demodulator (304) compensated by a pilot signal power (406). The apparatus performs the mitigation process by calculating (708) a pilot fading threshold in addition to a muting threshold. When samples of the mean pilot signal power fall below the fading threshold, the compensation of the demodulated signal is adjusted (714). In addition, when the mean analog message signal power falls below the muting threshold, the samples included in the predetermined portion of the message are muted (718).

Abstract: A method and apparatus implements a signal quality measurement (706) in a radio communication system for delivering a message (528) to a subscriber unit (122) in a coverage zone (402). In a fixed portion (102) of the system, for each coverage zone (402) of a group including the coverage zone (402) and other coverage zones (402) that are first tier co-channel interferers thereof, a silence slot is assigned in one of a plurality of synchronized signal quality measurement (SQM) slots. The assignment is such that within the group no two coverage zones (402) have the silence slot assigned to an identical one of the SQM slots. The fixed portion (102) transmits a silent signal from selected ones of the coverage zones (402) of the group in the silence slot assigned thereto, and transmits a predetermined signal from the selected ones in a remainder of the SQM slots not assigned thereto as the silence slot, and thereafter transmits the message (528).

Abstract: A method and apparatus for displaying directory-linked canned messages on a display (20) of a portable device (10) having selective call receiving functions. A personal name directory (100) is stored in the device (10). The name directory (100) comprises a plurality of entries (102), each entry comprising at least one telephone number and at least one canned message corresponding to the at least one telephone number. A paging message including a telephone number is received by the portable device (10). The personal name directory (100) is searched to determine if the telephone number received in the paging message matches with a telephone number in any of the personal name directory entries (102). If there is a match, the canned message which corresponds to the personal name directory entry that matches the telephone number received in the paging message is displayed. Otherwise, a default message is displayed.

Abstract: A communication system (100) encodes and decodes information utilizing at least four modulation levels for transmitting the information as symbols representing symbol bits in symbol bit positions. At least one of the symbol bit positions exhibits an error rate higher than that of another of the positions. A processor (204) encodes (702) the information into an even number of code words and transmits the code words as an interleaved data stream. The processor (204) rearranges (706, 708) the transmission order of the code word bits in a predetermined way to form a modified transmission order such that the code words are transmitted (710) with substantially equal error rates. A receiver (110) receives and demodulates (712) the interleaved data stream to derive the code word bits, and then reorders (714, 716) the code word bits to undo bit modifications resulting from the modified transmission order, thereby restoring the code words. The receiver then decodes the code words to recover the information.

Abstract: A method and apparatus remotely retrieves messages intended for an acknowledge-back pager (400, 700) in a communication system including a fixed portion (100) and the pager (400, 700). The communication system has provisions for interconnection with a user by telephone. The fixed portion (100) accepts (502) a selective call origination from a caller, including a message intended for the pager (400, 700) and sends (504) the message to the pager (400, 700) in response. The pager (400, 700) stores (506) the message within a pager memory (418). Thereafter the fixed portion (100) accepts (508) a selective call origination from the user, including a predetermined retrieval code associated with the pager (400, 700). The fixed portion (100) sends (510) a predetermined retrieval command to the pager (400, 700) in response, and the pager (400, 700) retrieves the message from the pager memory (418) in response.

Abstract: A communication receiver (100) employs a discrete time digital phase locked loop (142) for maintaining a generated signal (144) locked to a reference signal (136). The discrete time digital phase locked loop (142) includes a phase detector (202), an accumulator (219), an adder (227), and a controlled oscillator (232). The accumulator (219) is connected to the phase detector (202) and a reference signal (136) for calculating an accumulator output value equal to a first sum of a current sample generated by the phase detector (202), and all of the plurality of discrete phase error samples produced prior to the current sample. The adder (227) is connected to the phase detector (202) and the accumulator (219) for forming a second sum of the current sample and the accumulator output value. The controlled oscillator (232) receives the second sum, which is utilized for controlling the controlled oscillator (232).

Abstract: A method and apparatus for determining received signal strength of a radio frequency signal of a frequency dependent device to determine errors in automatic frequency control calculations. The method includes the steps of: 1 ) receiving the radio frequency signal; 2) providing at least two artificial thresholds based upon the signal during a first portion (45) of a signal block (32), wherein the artificial thresholds lie outside the peak and valley amplitudes of a demodulated intermediate signal (225) of the radio frequency signal; 3) providing automatic frequency control to determine a frequency error value (250) during a second portion (46) of the signal block (32); 4) determining a correction factor based upon the position of the demodulated signal in relation to the artificial thresholds during the second portion (46) of the signal block (32); and 5) varying the frequency of an adjustable crystal (220) in accordance with the correction factor applied to the frequency error value (250).

Abstract: A selective call receiver (105) for use in a selective call communication system (100) and a controller (206). The receiver (203) is for receiving and demodulating a digital signal which includes a predetermined sequence of A.times.N interleaved symbols representing a non-interleaved set of N tiers of symbols, each tier having A symbols, wherein A and N are positive integers. The controller (206) includes a deinterleaver (830) which reconstructs the non-interleaved set of N tiers of symbols from the demodulated signal, and a decoder (950) detects and corrects errors in the deinterleaved set of N tiers of symbols. The digital signal is transmitted simultaneously from two transmitters (103) having a difference frequency 1/P, and the symbols are transmitted at a rate of SPS symbols per second. The period of the difference frequency is given by P=(A.times.N)/SPS.

Abstract: A method and apparatus determine an instantaneous phase difference (207) between a reference signal (103) and a controlled signal (120). The reference signal (103) is derived by frequency dividing a first signal by a counter (106) including an output (107) having K sequential states, wherein K is an integer value equal to the frequency of the first signal (103) divided by the frequency of the desired reference signal, and wherein the output (107) changes by no more than one bit between any adjacent states of the K sequential states. The output (107) of the counter (106) is recorded (206) at a time concurrent with a first predetermined event occurring in the controlled signal (120), thereby generating a recorded count value that is free from metastability induced errors. The recorded count value is decoded (208) to produce a sequential state number S.sub.E corresponding to the first predetermined event. The instantaneous phase difference (207) is then calculated (210) from S.sub.

Abstract: A method and apparatus diversity-combine radio signals received from a plurality of branches (108, 214). Each radio signal comprises a plurality of subchannels (806). The radio signal from each branch (108, 214) is digitized (904) into digital samples that are converted (908, 910) into frequency domain signals (702, 712). Each frequency domain signal (702, 712) corresponds to a subchannel and a branch (108, 214). A weighting factor is determined (916) for each branch (108, 214) and each subchannel (806) from instantaneous signal energy and noise power calculated (912, 914) from the frequency domain signals (702, 712). The frequency domain signal (702, 712) corresponding to each branch (108, 214) and each subchannel (806) is multiplied (918) by the weighting factor therefor to produce weighted frequency domain signals corredponding to each branch and each subchannel.

Abstract: An electronic device (10) having a shielded housing (20) with an integrated light pipe (19 & 21) includes a substantially clear housing, a portion of which is arranged and constructed to form the integrated light pipe and plating (23), selectively applied to the substantially clear housing, to provide for effective electromagnetic interference shielding and to allow for sufficient light into the integrated light pipe.

Abstract: A voltage regulator circuit (100) for coupling to a power supply voltage (BPLUS) generates and regulates an output voltage (VREG). The voltage regulator circuit (100) includes a gain control element (148) for controlling the loop gain of the voltage regulator circuit (100) in response to the output current. Under heavy load conditions, the gain control element (148) functions to reduce (716) the output voltage (VREG) and thus the output current of the voltage regulator circuit (100) to avoid an overload that would pull the power supply voltage (BPLUS) below a predetermined level.

Abstract: A method and apparatus adaptively selects a communication strategy for communicating a message in a selective call radio communication system including a fixed portion (100) and a portable portion (101). The fixed portion (100) transmits (402) an alert signal to the portable portion (101), and awaits (404) an acknowledgment signal including a signal quality estimate from the portable portion (101). The portable portion (101) receives (602) the alert signal, and computes (604, 606) the signal quality estimate therefrom. The portable portion (101) then sends (608) the acknowledgment signal to the fixed portion (100). In response to the acknowledgment signal, the fixed portion (100) selects (407) a transmission strategy in accordance with the signal quality estimate. For compatibility, the transmission strategy requires a matching reception strategy in the portable portion (101).

Abstract: A method and apparatus in a radio communication transmitter (600) stabilizes a carrier frequency locked to a reference oscillator (102). The reference oscillator (102) is controlled by a control signal and generates a first signal at a reference frequency. The first signal is coupled to a frequency multiplier (212) for multiplying the reference frequency by a predetermined factor to generate a second signal at the carrier frequency. Cycles of the carrier frequency are counted (508, 514) during a predetermined interval to determine (516, 518) a measured cycle count. The measured cycle count is compared (520) with an expected cycle count corresponding to a predetermined carrier frequency to determine a drift error. From the drift error a control signal adjustment required to correct the drift error is computed (522). The control signal of the reference oscillator (102) is adjusted (524) by the control signal adjustment to correct the drift error.

Abstract: A method and apparatus in a receiver (110) for use in a selective call communication system (100) conserves battery power. The system (100) utilizes a signaling protocol (300) comprising a first bit and frame sync (320) transmitted at a predetermined baud rate, followed by a second bit and frame sync (322) transmitted at a second baud rate. The first bit and frame sync (320) defines the second baud rate. The receiver (110) synchronizes (406, 410) with the first bit and frame sync (320), determines (416) therefrom the second baud rate, and battery saves (420) during transmission of the second bit and frame sync (322) in response to determining that the second baud rate is equal to the predetermined baud rate.