Abstract: A messaging system (500) for transmitting a message to a subscriber unit (312). The messaging system (500) includes a plurality of geographically distributed messaging transmitters (302-310), each transmitter designed to transmit in a first modulation format, such as FM, during a first transmission portion (102) including address information; and in a second modulation format, such as OFDM, during a second transmission portion (104) including message data (110) transmitted in frames. The address information includes message characterization information (108) defining a predetermined frame rate. The second transmission portion (104) includes message data (110) transmitted in frames representing a time sequence of N data bits at the predetermined frame rate and provides a plurality of carrier frequencies related to a frequency domain representation of the time sequence of data bits. The predetermined frame rate numerically matches the predetermined symbol rate.

Abstract: A method and apparatus for testing integrated circuits by connecting a plurality of leads (25) of a device (10) to a test board (50). The test fixture (32) includes a test plate (70) having a plurality of test points (74) corresponding to the leads (25) of the device (10) and an alignment plate (60). The test points (74) are electrically connected to the test board (50) by a series of runners (76) extending from the test points (74) on the test plate (70) to a series of bumped finger pads (72) on the test plate (70). The bumped finger pads (72) of the test plate (70) are electrically connected to a series of bumped finger pads (54) on an active side (52) of the test board (50). The test plate (70) is fabricated of flex material. The alignment plate (60) is fabricated of flex material and is mounted on top of the test plate (70), so that the alignment plate (60) covers the runners (76), electrically insulating the runners (76).

Abstract: A frequency shift keyed receiver (214, 220, 218) estimates a carrier frequency and demodulates (1020) a symbol value associated with the carrier frequency. During symbol intervals, the receiver (214, 220, 218) receives a radio signal including symbol values (502-518) corresponding to predetermined frequency offsets (604, 606) from a carrier frequency. The radio signal is digitized (1008) during a symbol interval, and then converted (1010) into a frequency domain signal. The frequency domain signal is stored (1012), and additional symbol intervals are converted to obtain a plurality of frequency domain signals, which are processed to generate (1016) a composite frequency domain signal (702, 704). A windowing function (706) of predetermined shape is convolved (1018) with the composite frequency domain signal (702, 704) to locate a frequency distribution therein that corresponds to the predetermined frequency offsets (604, 606).

Abstract: A method and apparatus identify (822) respondents to a poll transmitted (806) in a radio communication system (100) comprising a transmitter (104) and a plurality of receivers (103, 105). A subset of a plurality of portable communication units (PCUs) (108) are each programmed (804, 806) with a bit pattern (510, 512, 514) corresponding uniquely to each PCU (108) and chosen such that when a group of at least two PCUs (108) are received simultaneously, the resultant received interference bit pattern provides a non-zero probability of correctly identifying at least a portion of the group, and a substantially zero probability of erroneously identifying a PCU (108) not in the group.

Abstract: A multiple display analog timepiece provided with a digital display (17) within the face (18) or watch crystal (13) of the timepiece (10) for displaying digital data (22), wherein the digital data (22) may be viewed without obstruction by the hands of the analog timepiece (10). The analog timepiece (10) includes an analog display (11) having at least two hands above the face (18) and below the watch crystal (13) of the timepiece; a digital display (17) within the face (18) or watch crystal (13) for visually presenting digital data (22); and motors (54) for selectively moving the hands between the position indicating the time and a read data position away from the digital data (22) when the digital data (22) is displayed on the digital display (17). The timepiece (10) may also include a radio frequency receiving device for receiving messages to be displayed as digital data (22).

Abstract: A method and apparatus improves the perceived quality of a voice message received in a radio signal by a radio communication receiver (108) having voice storage capability and operating in a fading signal environment. A monitor (203) repeatedly monitors (304) a received radio signal quality indication during intervals of reception of contiguous portions of the voice message, and a selective storage element (228) selectively stores (308) for later playback (404) only those portions of the voice message received during the intervals of reception having a radio signal quality indication higher than a predetermined threshold.

Abstract: A method and apparatus to control frequency deviation of a portable transceiver (PT) (122) utilizing a time-division-duplex (TDD) protocol for communicating with a base transceiver (116). The base transceiver (116) transmits (708) a first signal having first deviation levels (706). The PT (122) receives (802) the first signal, measures (808, 810, 824) it to derive estimates of the first deviation levels, and stores (826) the estimates in a memory (322). The PT (122) generates (828) a second signal having second deviation levels (830) controlled by control signal values (323), samples (832) the second signal to derive a second received signal, and appraises (902) the second received signal to derive estimates of the second deviation levels (830).

Abstract: A method and apparatus for minimizing mean calculation rate in a processing system (510) performing active addressing calculations on a frame of data for driving a display (100) having a plurality of electrodes (104, 106) comprise a monitor (700) for monitoring (1506) pixel values in the frame of data to be processed and displayed. A comparator (720) compares (1508) adjacent monitored pixel values to determine (1510) resolution of the data, and thereafter a controller (622) controls (1610, 1612, 1614) the processing system (510) to minimize the mean calculation rate by modifying the active addressing calculations in accordance with the resolution determined.

Abstract: A low-voltage IF amplifier (112) provides automatic gain control (AGC) of a source amplifier (104) supplying an IF input signal to the IF amplifier (112). The IF amplifier (112) includes cascaded amplifier stages (202) that include an amplifier element (344) having an input (122) for receiving a stage input signal, and an output (124) for generating an amplified stage output signal in response. The amplifier stages (202) also include a received signal strength detector (346), or RSSD, for generating a gain control current responsive to the stage input signal. The IF amplifier (112) also includes a current summer (206) for summing the gain control currents generated by the RSSDs (346) to produce a total gain control current, and a gain control element (204) that controls the gain of the source amplifier (104) in response to the total gain control current, such that signal levels within the source amplifier (104) are maintained within a linear operating range.

Abstract: A method and apparatus minimize false detection of packet data in a receiver (202) due to noise in a communication system (100) utilizing time slots (420). Some time slots (420) contain a data packet (418), while others contain only noise. The data packet (418) includes a sync word (602) and an error-detecting code word (604, 606, 608). The receiver (202) is synchronized (1006, 1008) with a nominal predetermined timing of the time slots (420), and determines (1014) time windows (808) for receiving the data packets (418). During each of the time windows (808) data is received, demodulated, and stored (1016), and a predetermined portion of the data stored is searched (1018) to locate a point of maximum correlation between the data and a data template (902) matching the sync word (602).

Abstract: A detector circuit (301) is utilized in a DC to DC converter (300) having an inductor (356) coupled to a switch (358) for interrupting an electric current through the inductor (356), thereby allowing the inductor (356) to transfer stored energy to a capacitive load (364). The detector circuit (301) includes a capacitor (302) coupled to the inductor (356) for generating a transient current (428) in response to a completion of a transfer of stored energy from the inductor (356). The detector circuit (301) further includes a reference current generator (306) for generating a reference current, and a summing node (304) coupled to the capacitor (302) and coupled to the reference current generator (306) for summing the transient current (428) and the reference current. The two summed currents form a transient control current (436) responsive to the completion (424) of the transfer of stored energy from the inductor (356).

Abstract: A method and apparatus control message transmissions in an acknowledge-back selective call communication system (100) including an infrastructure (102) and a selective call receiver (120). The selective call receiver (120) stores received messages in a memory (322). The infrastructure (102) transmits (604) to the selective call receiver (120) information including the length (408) of a pending message, and the selective call receiver (120) determines (606) therefrom a response (412, 504) based upon the length (408) of the pending message and memory space available in the memory (322). The selective call receiver (120) transmits (608) the response (412, 504) to the infrastructure (102), and the infrastructure (102) controls further processing of the pending message in accordance with the response (412, 504).

Abstract: In a radio telephone (100, 200) having a keypad (206) for receiving first information (302), a memory (112) for storing second information (313), and an intelligent editing function. There is provided a method of transmitting information representing a phone number using the intelligent editing function that selects a prefix mode when a phone number has been automatically entered and selects an appending edit mode when the information representing a phone number has been manually entered. The information is then edited to form a complete phone number (315), and transmitted (102, 104, 105, 106).

Abstract: A method and apparatus for closed loop frequency control in a two-way radio communication system (100) include a base communication unit (104) and a portable communication unit (108) having a portable-to-base initiation channel (202) assigned to a predetermined frequency. A signal is transmitted (502) from the portable communication unit (108) to the base communication unit (104) on an initiation frequency of approximately the predetermined frequency. The base communication unit (104) determines (506) from the signal a frequency correction factor (326) for recalibrating the initiation frequency in accordance with the predetermined frequency. The frequency correction factor (326) is communicated (512) to the portable communication unit (108), and the portable communication unit (108) recalibrates (516) the initiation frequency in response.

Abstract: A method and apparatus in a data communication receiver (100) for diversity reception of a radio signal including a predictably repetitive, predetermined data bit pattern (304) comprises a processor (114) controlling (600) an antenna switch (106) to select between a first antenna feed (102) and a second antenna feed (104) as a momentary source of the radio signal during transmissions of the predetermined data bit pattern (304). The radio signal received from the momentary source is monitored by a data receiver (110) during the transmission of the predetermined bit pattern (304) to derive the data therefrom, and at least one bit error count is determined (604, 610) by the processor (114). After completion of the predetermined bit pattern (304), an antenna feed (102, 104) for the radio signal is selected (616, 620) in response to the at least one bit error count.