Patent ID: 8588333
Filing Date: 2013-11-19
Classification: H03F,H04L

Abstract:
1. A linear RF transmitter including a forward path for receiving and processing in an operational mode an input baseband signal and for producing a modulated RF signal from the baseband signal, the forward path including a baseband signal combiner and an RF (radio frequency) power amplifier, a linearizing control loop including a coupling from an output of the RF power amplifier to an input of the combiner, wherein the control loop includes a feedback control path operable to deliver a baseband error control signal to the combiner, the transmitter further including a test signal generator operable to apply to the combiner in a closed loop level training mode a test signal comprising a voltage waveform V in which increases with time in a non-linear manner approaching an asymptotic limit such that in response an output signal produced by the combiner is a voltage V e which is substantially constant over a period of time.