Abstract: A device (100) includes detachable main and auxiliary batteries (101, 102) and a circuit (310) for discharging and charging the batteries (101, 102). Discharging is accomplished by an auxiliary switch (420) that connects the auxiliary battery (102) to power the device (100), a detector (422), and a main switch (424) that connects the main battery (101) to power the device (100), without interruption, when the auxiliary battery (102) drops below a predetermined voltage (508) as determined by a detector (422). Charging is performed by switches (440, 442, 446), an internal charger (444), and a controller (306). When both batteries (101, 102) are attached, the controller (306) uses the switches (440, 442, 446) to select and couple charging current generated by the internal charger (444) to the main battery (101). Once charged, the controller (306) switches to charge the auxiliary battery (102).

Abstract: A unique method and apparatus modifies the load impedance at the output of a power amplifier by varying a voltage variable capacitor (VVC) (310) to maximize the efficiency of the power amplifier (304). A comparator (509) generates amplifier control signal (211) based upon a detected power output signal (216) and a reference signal. In addition to providing power control, the control signal is also coupled to a VVC circuit (506) to control the output impedance of the power amplifier. In an alternate embodiment, a separate VVC control signal (527) based upon a comparison of the power control signal and the battery voltage is coupled to a VVC. In another alternate embodiment, a second VVC can be coupled in parallel to the first VVC. The second VVC is preferably controlled by a signal (805) based upon the current in the power amplifier.

Abstract: A novel conductive contact comprises a dual beam spring (308, 310) which forms a "C" shaped spring and which is used to electrically mate to a contact on a printed circuit board. The open end of the "C" spring preferably fits over a plastic rib (404) in a housing for support. A surface mount contact (504) on the PCB has formed wings which fit into a rectangular slot in the PCB. To make electrical connection, the board is placed over the "C" spring. The "C" spring and plastic support protrude through the rectangular slot in the PCB. The conductive contact is preferably formed from a single piece of metal.

Abstract: A unique cellular telephone billing system (100) processes call detail records (102) of cellular telephone calls made by users of customers to produce invoices and reports containing consolidated billing, usage and cost information for the current and other eligible cellular service plans. Eligible cellular service plans are identified for each user in a candidate file and costs for accumulated usage data are calculated (216) under the current and eligible cellular service plans. The calculated costs for the current and eligible cellular service plans may then be compared to determine the most cost effective service plan for each user on the basis of peak and off-peak usage and customer discounts. Reports may be generated (218) for each user illustrating consolidated billing, usage and cost information by sorting on the basis of the corresponding key identification number and information format.

Abstract: A unique method and apparatus for charging a battery enables the safe and efficient charging of a battery (102) which may be removed during charging. An electronic device (106) may not be adapted to be powered by the external power supply (114) without a detachable battery, or more importantly, the internal circuitry (200) may be damaged when the detachable battery is removed while the power supply is attached. Also, a battery may not be properly charged if a battery is replaced in the middle of a charging program for the battery. By periodically interrupting (306) the charging current, a device may turn itself off before circuitry or components are damaged if a battery is removed, and reset the charging program to correctly charge a battery if the battery is replaced.

Abstract: The process of the present invention computes the update to the least mean square channel estimator taps. The update coefficient for each tap is computed independently based on the power of each tap relative to the main tap power.

Abstract: A method and apparatus increases spectrum efficiency in a wireless communication system having base stations which may be positioned to operate within range of one another. The method and apparatus eliminates the requirement for a base station to periodically transmit to maintain synchronization with an associated handset (504). The handset effectively assumes the role of a base station when making a call (508). The handset will synchronize with other handset traffic or another base station which is within range (506). The handset will then page the base station (510). Eliminating the requirement that the base station repeatedly transmit a signal to maintain sync with a handset significantly increases the available spectrum allocation for providing communication. Reversing the role of a handset also enables handset-to-handset communication independent of the base station (808).

Abstract: A communication system has a PCC 101 which receives a data stream from a cordless base station 115. The cordless base station 115 transmits an indication in the data stream that it is going to begin a scan. While the cordless base station 115 is scanning, the PCC 101 performs a scan of its own. The PCC 101 also performs a scan when it determines that a message is a repeat and has been previously received.

Abstract: In summary, the present invention provides a method and apparatus for determining an external power supply type and modifying the charging of the internal battery (14) based upon the external power supply type and battery information. The device has an external power adapter (12) used to provide power to the device (10), as well as charging current for the battery which is regulated by the internal battery charger. A microcontroller (20) in the device (10) regulates the charging current to the battery (14). The microcontroller (20) preferably contains an A/D converter (21) which is connected to a pull-up resistor (32) internal to the device, and to a pull-down resistor (34) in the external power adapter (12). The voltage generated by the resistor divider network including the pull-up resistor (32) and the pull-down resistor (34) in the external power adapter is used to identify the external power adapter type.

Abstract: A tuning circuit for a reference oscillator (200) including voltage variable capacitors (222, 224) in a back to back configuration and providing a control terminal for voltage controlled tuning of the reference oscillator (200). Also included in the tuning circuit is a modulation bias circuit for modulating the reference oscillator (200).

Abstract: A unique method and apparatus determines signal quality and/or bit reliability information for a plurality of phase modulated information symbols. This is accomplished by first detecting the phase of the received phase modulated signal (201). The resulting phase estimate is then compared against the nearest expected phase value to form a phase error signal (202). The phase error signal is then mapped into a symbol quality estimate (205/206), which is then averaged over multiple symbol intervals to form a signal quality indicator (207). Finally, bit reliability information is generated by weighting the in-phase (I) and quadrature (Q) components of the phase estimate by the derived signal quality indicator (209). With such a method and apparatus, signal quality and/or bit reliability information can be determined without the need for signal amplitude information.