Patent ID: 6091298
Filing Date: 2000-07-18
Classification: H03F

Abstract:
A linear power amplifier arrangement comprising an input line, a power amplifier, an output line, an input tap and an output tap, first and second mixers, and a feedback circuit comprising a delay element, a first splitter, a second splitter, a phase control circuit and an amplitude control circuit,;wherein the first and second mixers are placed on the input line between the input tap and the power amplifier;wherein the phase control circuit comprises a phase comparator, a phase control amplifier and a divider;wherein the phase comparator is arranged to receive delayed phase signals from the input, Aexp(i.alpha.), and the feedback signal, Bexp(i.beta.), and is arranged to provide output signals AB sin .THETA. and signal AB cos .THETA. (where .THETA.=.alpha.-.beta.);wherein the phase control amplifier is arranged to receive the signal AB sin .THETA. from the amplitude comparator which is arranged to output a signal to the divider, and;wherein the divider is arranged to receive a control signal corresponding to signal AB cos .THETA. and is arranged to provide a phase error signal, tan .THETA., to be multiplied by the first phase correcting mixer;wherein in use:the input tap obtains a portion of the input signal, which portion is delayed by the delay element and split into phase and amplitude components;the output tap obtains a portion of the output signal from the high power amplifier as part of the feedback circuit which signal is split into phase and amplitude components; andwherein the delayed input signal amplitude component is combined with the feedback amplitude component by the amplitude control circuit to produce an amplitude correction signal which is mixed with by the second, amplitude correcting, mixer.