Abstract: An envelope tracking amplifier for a transmitter has a voltage mapping linearly related to the square of the amplitude of the baseband signal.

Abstract: A method of providing a power supply of an amplifier of a wireless transmission system comprising, determining the power at an antenna when transmitting a signal to be transmitted by the amplifier, determining the modulation scheme for transmitting the signal, determining the frequency allocation of the signal to be transmitted, determining a transmit channel characteristic, and adjusting a parameter of the power supply of the amplifier based on the determining steps to maintain amplifier linearity.

Abstract: An apparatus and method for reducing unwanted spectral emissions of a complex signal to be transmitted comprising calculating the nth power of the complex signal to be transmitted, calculating the complex conjugate of the nth power of the complex signal to be transmitted, applying a scaling factor to the complex conjugate to form a scaled correction signal, and adding the scaled correction signal to the signal to be transmitted.

Abstract: An integrated circuit device has an LC tank circuit for frequency determination, and a switched capacitor circuit for tuning the resonant frequency of the LC tank. The switched capacitor circuit has plural sets of parallel branches, each set comprising a first branch and a second branch, the first and second branches each connecting between a first node and a second node, each branch containing a respective capacitor in series with a switch, the switched capacitor circuit being configured such that, in use, the switch of the first branch is on when the switch of the second branch is off and vice versa.

Abstract: An envelope tracking amplifier for a transmitter has a voltage mapping linearly related to the square of the amplitude of the baseband signal.

Abstract: A gain-controlled RF amplifier system has an input node and an output node. The system has a plurality of amplifier devices, selectively connectable between the input node and the output node. The amplifier devices are placed in circuit according to a measured gain derived by comparing a magnitude of a signal input to the input node against a magnitude of a signal output from the output node, and a desired value of gain.

Abstract: A gain-controlled RF amplifier system has an input node and an output node. The system has a plurality of amplifier devices, selectively connectable between the input node and the output node. The amplifier devices are placed in circuit according to a measured gain derived by comparing a magnitude of a signal input to the input node against a magnitude of a signal output from the output node, and a desired value of gain.