Abstract: An automatic digital level control adjuster (310) processes an analog input signal (305) to adjust its signal level, based on input (311) from a digital module (330) that is clocked by a clock signal (325) derived from the analog signal (305). Preferably, the input (311) from the digital module (330) changes at a rate dependent on the clock signal (325), and such changes are made during crossovers of the analog signal across a predetermined zero reference threshold.

Abstract: A subscriber unit automatically selects repeater access mode, if a repeater is available, or talk-around mode, if a repeater is not available (500). The subscriber unit initiates a call by transmitting a call setup request on the outbound channel used by the repeater (510), and by monitoring the outbound channel to detect a response from the repeater (520). If a response is received within a timeout period, the subscriber unit continues the call by transmitting on the inbound channel (530, 540). Otherwise, the subscriber unit continues the call using talk-around mode, by transmitting on the outbound channel (530, 550). In this process, the repeater monitors the outbound channel to determine when a call setup request is transmitted by the subscriber unit (610), and responds accordingly on the outbound channel (620, 630), thereby indicating its availability.

Abstract: A communication device (104) is provided which incorporates a hovel method for selecting a preferred communication site from available communication sites (110, 120, 130) within a wireless communication system (100). The communication device (104) receives a communication signal from at least two of the available communication sites (110, 2120, 130). A preferred communication site (420) is selected using fuzzy logic based in part on the received communication signal (216).

Abstract: A subscriber unit (405) operating within a radio communication system (600) supplements neighbor list information received from a cell site (428), when that cell site (428) is expected to provide inadequate neighbor cell list information. When the subscriber unit (405) obtains a new neighbor cell list (442) from the cell site (428), it determines whether characteristics of the cell site (428) is such that the new neighbor cell list (442) does not adequately reflect available neighboring cell sites. Such a condition is presumed to exist for a cell site designated as a high site. In such cases, the subscriber unit combines entries from its current neighbor cell list (451) with entries from the new neighbor cell list (442) obtained from the cell site to generate a supplemented neighbor cell list (652). The supplemented neighbor cell list (652) is used to monitor potential server sites, and to make hand-over decisions.

Abstract: A differential circuit (200) provides for reverse isolation between input and output ports (202, 204). The differential circuit has amplification circuitry that includes active transistors (221, 222) and reverse isolation circuitry that employ transistors (223,224) having similar manufacturing and processing characteristics to couple the input and output ports (202, 204).

Abstract: A radio communication system (100) has an information display interface (201) to provide operator assisted operational control. The information display interface (201) has multiple control sheets (240, 250) each containing an operator configurable category of radio system control information. A particular control panel (263) for controlling a particular portion of the radio communication system is co-located on multiple control sheets (240, 250). One of the control sheets (240) is made active and displayed in a foreground display mode. Operational control of the particular portion of the radio communication system (100) is conducted through the particular control panel (263) on the active control sheet (240).

Abstract: A subscriber (410) to a radio communication system manages information needed to monitor for potential server sites during an ongoing communication session. Upon switching server sites during an ongoing communication (520, 530, 540, 550), the subscriber uses a modified neighbor site list for subsequent monitoring for potential server sites (570). The modified list is generated from the original list without benefit of new information downloaded from an external source, by replacing information representing the new server site with information representing the old server site (560).

Abstract: A communication system (120, 125) worn by a user (110) includes a base device (120) and an earpiece (125), which are spatially separated but coupled by a communication link. The base device (120) is operable in first and second operating modes (410). When in the first operating mode, the base device (120) receives and presents text based messages in human readable form to the user via a user interface associated with the base device (420, 430, 435, 440). When in the second operating mode, the received message is converted to audible form, preferably using a text-to-speech synthesizer, and presented to the user via the earpiece (430, 455, 460, 465).

Abstract: A method for re-programming a memory device in a micro-controller system is provided. The method includes the steps of installing a software RTC service routine running outside the flash memory device, wherein a counter measures the total re-programming procedure duration (100). The software RTC service routine running outside the flash memory device is stopped (102) and the current absolute unit time saved in a read/write accessible memory cell (104). A re-programming cycle is executed (106) and the former running application will be prepared to continue (108). The unit is set to the previous stored value (110) and the software RTC service routine running outside the flash memory device re-started (112). The software RTC service routine running outside the flash memory device is stopped (114) and the measured total re-programming duration added to the current RTC value (116). The application then recommences (118).

Abstract: A communication device (122) supports secure communications using automated encryption key scheduling. The communication device (122) is provided with access to one or more schedules having entries of specific time periods, such as date and time of day information, that govern selection of encryption keys. A schedule is selected and accessed using current time information to obtain an encryption key (310, 320, 330). Subsequent communications are conducted using the obtained encryption key (340).

Abstract: A quadrature generator (100) includes a phase detector (125) having a set of differential inputs for coupling in-phase and quadrature signals (114,116) and a set of differential outputs for providing a phase error signal (135). Switches (122,127) are associated with the set of input terminals and with the set of output terminals. The switches (122,127) are synchronously controlled to switch around the signals at the input terminals and at the output terminals in concert, and in rapid succession. The operation of the switches (122,127) eliminates or reduces the effects of imperfections within the parallel paths of the phase detector circuitry (125), in order to produce a more accurate phase deviation signal.

Abstract: A bi-directional voltage translator (125) has a first port (201) that communicates a signal at a first voltage level, and second port (202) that communicates a signal at a second voltage level different from the first voltage level. A switching circuit, including a bipolar junction transistor (210) and a switch (220), couples both ports (201, 202). The transistor (210) has a collector (211) coupled, via a pull-up circuit (206), to a voltage source corresponding to the first voltage level, and to the first port (201), and an emitter (212) coupled to the second port. The base (213) of the transistor (210) is coupled, via a pull-up circuit (207), to a voltage source corresponding to the second voltage level. Preferably, the switch (220) is Schottky diode or other diode having a forward voltage drop.

Abstract: Second order intermodulation distortion (IM2) occurs when two interfacing signals mix with each other through a second order nonlinearity to produce an intermodulation product at the sum and difference frequencies of the two interferers. To reduce the amount of intermodulation distortion, dynamic matching is employed. In practice, dynamic matching operates to transform coefficients of IM2 distortion from constant values into functions of time where they may be handled by known rejection techniques.

Abstract: Communication resources are allocated within a radio communication system in anticipation of expected resource requirements using predictions based on information supplied by a subscriber unit. In one embodiment, the system uses the subscriber unit's location history to predict a future location (510, 520, 530). In another embodiment, the system uses radio capability information, along with environment information for the subscriber unit, to predict loading conditions for potential hand-over sites (610, 620, 630), and assigns the subscriber unit to one of the potential hand-over sites based on the predicted loading conditions (640).

Abstract: An apparatus (100) includes a differential processing circuit (135) responsive to an input signal with first and second signal components, and a signal imbalance suppressor (130) that preprocesses the input signal, prior to input to the differential processing circuit, to remove amplitude and/or phase imbalances that exist between the first and second signal components, in order to reduce even order distortion generation within the differential processing circuit.

Abstract: A SONAD (110) control system (100) detects a received signal strength (RSSI) for a radio frequency (RF) signal (102), selects a threshold transfer function (400-404) in response thereto, generates a threshold control signal in response to the transfer function, and utilizes the threshold control signal to select the SONAD threshold value. During operation, the control system (100) decreases the attenuation of background noise levels for weak RF signals.

Abstract: A communication device (10) for receiving or transmitting radiofrequency (rf) signals has a transceiver (12), signal processing circuitry (14) and a signal switch assembly (16). Assembly (16) has a jack (18), an antenna matching circuit (20) and a bypass circuit (22). Rf signals are provided to transceiver (12) through antenna matching circuit (20) when an antenna is connected to jack (18). However, antenna matching circuit (20) is bypassed so that the rf signals are provided to transceiver (12) through bypass circuit (22) when a connector from a signal cable is connected to jack (18). Bypass circuit (22) is actuated as such when a ground member of such a connector electrically connects a ground contact (26) and one other contact (28) within jack (18). Ground contact (26) and other contact (28) are annularly disposed around a signal contact (24) of jack (18).

Abstract: A subscriber (125) to a radio communication system (110) is automatically notified of an event affecting or potential affecting a particular geographical locality. The radio communication system obtains such event and locality information (310, 320), and uses the locality information to transmit the event information to subscribers of that system potentially affected by the event. In one embodiment, the system automatically uses only transmitters that service at least a portion of the affected locality to transmit the event information (330, 340). In another embodiment, the system automatically transmits event information selectively to those subscribers having a location designation corresponding to the particular locality (410, 420).

Abstract: A parameter extraction technique for an electrical structure is based on a definition of network parameters that isolates pure mode responses of the electrical structure, and that makes mode conversion responses of the electrical structure negligible. A set of network parameters is obtained that represents pure mode responses for the electrical structure (410). These network parameters are processed to obtain model parameters that characterize each pure mode response (422, 424, 426, 428, 432, 434, 436, 438). Preferably, the mode specific parameters to combined to obtain mode independent parameters, such as coupling factor, propagation constant, and characteristic impedance values (440, 450).