Abstract: A system for operating a cellular phone using Bluetooth with a car kit is described. The Bluetooth protocol is used to communicate between the cellular phone and the car kit. A communication can be established between the cellular phone and the said car kit. In one mode, the car kit can be made to assume the identity of the cellular phone and transmit as if it were the cellular phone itself. In another mode, the car kit can become a hands-free set for the cellular phone which communicates with the cellular phone via Bluetooth.

Abstract: A call time usage system for a portable telephone allows entering call time usage information into the portable telephone. The limits include limits on total airtime and airtime per call for a specified interval. After the specified interval, the limits are reset. A list of exempt numbers is also stored so that the user can call those exempt numbers even after the limit is exceeded.

Abstract: An antenna system for an automobile uses an external antenna that is either connected to the cell phone directly, or connected to a passive antenna that communicates with the cell phone.

Abstract: A portable electronic device has at least one battery pack with each pack having its own capacity gauge. A reserve power option system monitors power level information received from the capacity gauge to determine if the portable electronic device should be transitioned into a power-saving, low-current mode.

Abstract: A radio transceiver having an event-driven power control circuit that commands a digital processor to perform power control processing only when the output power exceeds a predetermined power range.

Abstract: A system for determining the location of portable communication devices such as cellular telephones and the like has multiple small, dedicated multipath calibration transponders at known positions. When a portable communication device initiates a call, base stations in the coverage area direct the transponders to generate response signals which are received by the base stations. The characteristics of the signals from the portable device and the transponders are provided to a base station controller linked to the base stations. The base station controller derives a coarse position using the raw device position information and uses the raw transponder position information and the transponder's known positions to derive a correction vector representative of multipath distortion of transponder signals in the area of the portable device.

Abstract: A docking adapter couples a PCS system to an external antenna via the PCS system's portable antenna. When the portable antenna is extended from the body of the PCS unit, it functions as a normal vertical dipole antenna. When it is retracted into the unit's body, a connector at the tip of the portable antenna makes electrical contact with the PCS transceiver. The tip connector may be connected to an external antenna, thereby providing a transmission path from the PCS transceiver to the external antenna.

Abstract: A circulator section in a transceiver receives a transmit signal and an antenna signal and provides them respectively to an antenna and to an electronic switch. The electronic switch operates synchronously with the duplex mode of the transceiver to connect the antenna to a receiver when the transceiver is in receive mode, and to a matched load when it is in transmit mode. Since the signal path of any portion of the transmit signal reflected by a mismatched antenna is terminated by the load, power which otherwise might be reflected back to the transmitter and thereby damage it is instead absorbed by the matching load.

Abstract: A dynamically reconfigurable frequency division multiplexer and modulator accepts multiple input signals, each of which is individually time division multiplexed. Each input signal is used to modulate a carrier signal having a unique frequency. Switches are used to selectively form one or more groups from the modulated signals, and the signals in each group are frequency division multiplexed by summing them together. In a Personal Communication Service environment, the output for each group may be fed to a respective antenna and the switches and carrier signals controlled to selectively associate inputs signals, carrier frequencies and antennas to implement antenna diversity operations and compensate for signal degradation due to multipath propagation effects.

Abstract: An FET with multiple channels to provide a substantially linear transfer characteristic. The widths and carrier concentrations of the channels, and the depths of the channels below the gate of the FET, are adjusted such that a substantially linear gate voltage-to-output current (drain) transfer characteristic of the FET results. In addition, the electrical characteristics of the FET may be adjusted by changing the spacing of the drain and source diffusions from the gate.

Abstract: An FET with multiple channels to provide a substantially linear transfer characteristic. The widths and carrier concentrations of the channels, and the depths of the channels below the gate of the FET, are adjusted such that a substantially linear gate voltage-to-output current (drain) transfer characteristic of the FET results. In addition, the electrical characteristics of the FET may be adjusted by changing the spacing of the drain and source diffusions from the gate.

Abstract: A reduced loss coupling technique for combining multiple, parallel, gain-stages to form an amplifier. A first transmission line, with multiple taps, couples the inputs of the gain-stages together and to an input port for the amplifier. A second transmission line, also with multiple taps, couples the outputs of the gain-stages together and to an ouput port for the amplifier. Preferably, the output port is connected to the end of the second transmission line while the input port is connected asymmetrically (off center) along the first transmission line. The actual position of the input port along the first transmission line is determined by the desired amount of phase mismatch of between signal paths through all of the gain-stages as measured from the input port to the output port.

Abstract: Amplifier-produced distortion known as amplitude modulation to phase modulation (AM/PM) conversion is reduced through the use of GaAs FETs which are biased to generate AM/PM having an algebraic sign opposite to that generated by the amplifier. This algebraic sign reversal is accomplished by biasing the GaAs FETs so that a DC drain current .ltoreq.75% and .gtoreq.10% of the short-circuit drain current is established. In the disclosed embodiment, several GaAs FETs are cascaded in alternation with attenuators to increase the magnitude of the compensating AM/PM conversion without generating substantial amplitude modulation to amplitude modulation (AM/PM) conversion.

Abstract: A single adjustment phase resolver uses common voltage control in a dual inversely tracking bridged-Tee attenuator circuit (21) to provide a variable relative phase displacement between two output signals whose amplitude levels are maintained equal and constant throughout the range of the phase adjustment. The dual bridged-Tee attenuator is implemented using two variolossers wherein the PIN diodes are serially connected in two pairs (51 and 52, 53 and 54) and the pairs are oppositely poled from one another. An automatic gain control circuit (16, 24 and 26) adjusts the input signal level to compensate for a latitude of discrepancy between the inverse tracking variolossers.