Linear Power Amplifier Based on Analog Cancellation

Abstract

The invention discloses a linear power amplifier based on analogue cancellation. The amplifier comprises a first coupler, a second coupler, a third coupler, a fourth coupler, a fifth coupler, a sixthcoupler, a seventh coupler, a main power amplifier, an error power amplifier, a first power divider, a second power divider, a first synthesizer, a second synthesizer, a third synthesizer, a first attenuator, a second attenuator, a first delay line, a second delay line, a third delay line, a first vector modulator, a second vector modulator, a third vector modulator, a first correlation detectioncontroller, a second correlation detection controller and a third correlation detection controller. Adaptive ability of a circuit to external environment and circuit parameter variations is kept via dynamic optimization of the correlation detection controllers and the vector modulators, and the optimal and stable linear effect of the power amplifier is achieved.

Description

technical field [0001] The invention belongs to the technical field of electromagnetic compatibility, and in particular relates to a linear power amplifier based on analog cancellation. Background technique [0002] Power amplifier (power amplifier, PA), as an important front-end active part of the wireless transmission system, usually works in a saturated state, and its linearity directly affects the signal quality of the transmission link, and further affects the signal-to-noise ratio of the link and the bit error rate at the receiver. Especially with the development of broadband communication technology, Code Division Multiple Access (CDMA) with Peak-to-average power ratio (PAPR), Orthogonal frequency division multiplexing (Orthogonal frequency division) Multiplexing, OFDM) and other broadband time-varying envelope signals cause serious nonlinear distortion to the PA working in the saturation region, resulting in an increase in the bit error rate in the band, serious out...

AI Technical Summary

Problems solved by technology

[0010] (1) The control accuracy is limited by the number of ADC / DAC digits, and the nonlinear cancellation ratio is limited due to the limited back-end processing power provided by the digital circuit;

[0011] (2) The effective bandwidth of linearization is limited by the sampling frequency and working bandwidth of devices such as DC / DAC;

However, there are two serious defects in this method: (1) the design is difficult, and the gain flatness of the error power amplifier and the phase shift linearity of the vector modulator are extremely demanding

Since the intermodulation of the pilot and carrier signals will introduce new intermodulation distortion and intermodulation distortion parameters, especially the third-order intermodulation output will fall into the passband of the useful signal and cannot be eliminated, and a new distortion parameter is introduced; (3) Debugging is difficult, because the error power amplifier and vector modulator will show different characteristics with the change of working conditions, resulting in the inability to accurately guarantee the flatness of the gain and the linear phase shift of the vector modulator in the actual design and production debugging process characteristic

Therefore, this kind of analog linear power amplifier based on pilot cancellation has poor stability and is difficult to produce

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