Nokia Mobile Phones Limited

Qualcomm Incorporated

John A Samuels

Peter Sroka

A method and apparatus for receiving a radio frequency signal and a method and apparatus for transmitting a modulation signal in a multiple channel radio system. The method for receiving the radio frequency signal involves mixing the radio frequency signal with a demodulating signal, tunable in frequency steps greater than the channel spacing of the multiple channel radio system to facilitate rapid frequency adjustments. The resultant intermediate signal is then mixed with another demodulating signal, tunable in relatively smaller frequency steps in order to select the channel containing the radio frequency signal.

Method and apparatus for transmitting and receiving signals

A dual mode radio frequency receiver or transmitter capable of operating in a terrestrial mode in which signals are routed over a terrestrial network, and a satellite mode in which signals are routed over a satellite network. The radio frequency receiver includes a terrestrial front-end RF stage which receives signals from a terrestrial network, a satellite front-end RF stage which receives signals from a satellite network, and a common RF stage which includes mixing circuitry for frequency down-converting the signals received from the front-end RF stages.

Radio receiver and radio transmitter

An amplifier system for a radio receiver, comprising: an amplifier chain having a first amplifier for receiving a signal derived from a received radio signal and amplifying it to generate a first amplifier signal, and a second amplifier for receiving a signal derived from the first amplifier signal and amplifying it to generate a second amplifier signal; a sensor means for sensing the level of a signal at a point in the amplifier chain; and amplifier control means responsive to the sensor means for, when a relatively high level of signal is sensed, controlling the first and second amplifiers to improve their response.

Amplifier system

An amplifier system for a radio receiver, comprising: amplifier means for amplifying a signal applied to an amplifier input to generate an amplifier output signal; and control means for sensing the amplifier output signal and, in response to a relatively high level of the output signal, controlling the current applied to the amplifier input to maintain the amplifier means in a linear mode of operation.

An amplifier system for a radio receiver, comprising: an amplifier for amplifying a signal applied to an amplifier input to generate an amplifier output signal; a variable reactance means coupled between the emitter or source of the amplifier and a ground voltage; and a feedback loop for sensing the amplifier output signal and, in response to a relatively high level of the output signal, controlling the reactance of the variable reactance means to maintain the amplifier in a substantially linear mode of operation.

Amplifier system with controlled reactance

In a mobile radio telephone, an adaptive impedance matching circuit (25) is positioned between a transmitting power amplifier (24) and a duplexer (18). The adaptive matching circuit (25) matches an antenna (17) to associated electronic circuitry, thereby optimising power transfer in an effort to maintain communication with a base station and to minimise power dissipation within the device itself. An adaptation algorithm is selected and implemented during idle periods when a reflection coefficient is identified as being large. The reactance of a passive pi network is incrementally modified and settings which achieve an optimum match are stored for subsequent use.

Growing community of inventors

Surrey, United Kingdom

John A Samuels