Samsung Electronics Co., Ltd.

Yong-chae Jeong

Jun-Seok Yang

Young Kyoo Kim

Ik-Soo Chang

Ik-hee Park

Myung-gu Choi

A method and apparatus for amplifying a feedforward linear power using a pilot tone hopping are disclosed. The method in a feedforward linear power amplifier system first determines an operating frequency signal for amplification from a radio frequency (RF) signal applied to the linear amplifier system. A pilot frequency signal is determined from the previously determined operating frequency signal, and the decided pilot frequency signal is hopped into an upper sideband or lower sideband of the operational frequency bandwidth of the applied RF signal and the determined pilot frequency signal is output to an input port of a main amplifier. One typical advantage of the method is that distortion component suppression characteristics in the wide operating frequency bandwidth are obtained by only one pilot signal generator and use of a control/detect device leads to simplicity of the circuit.

Method and apparatus for amplifying feedforward linear power using pilot

An RF signal offset circuit using a half wavelength transmission line is provided. The RF signal offset circuit includes an RF transformer having an input coil and an output coil. The input coil has first and second input ports. The output coil has first and second output ports. One of the output ports is grounded. A half wavelength transmission line having first and second ends is connected in parallel to the input coil of the RF transformer. First and second resistance devices are respectively connected between the first end of the transmission line and the first input port of the RF transformer and between the second end of the transmission line and the second input port of the RF transformer.

RF offset circuit using a half wavelength transmission line

A feedforward-type linear power amplifier directly compares amplitude and phase of a signal applied to one input end of a first signal canceler with amplitude and phase of a signal applied to another input end of the first signal canceler, and according to the comparison results, controls a first variable attenuator and a first variable phase shifter disposed in a pre-stage of the first signal canceler so that the first signal canceler extracts only the intermodulation distortion signals generated while a main power amplifier amplifies the RF input signal. Then, the linear power amplifier directly compares amplitude and phase of the intermodulation distortion signal on a main path with amplitude and phase of the intermodulation distortion signal on a sub path, and according thereto, controls a third variable attenuator and a third variable phase shifter to cancel the intermodulation distortion signals contained in the RF output signal of the main power amplifier.

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Anyang, South Korea

Yong-chae Jeong