Pre-distorted radio frequency amplifier

Abstract

The invention discloses a pre-distorted radio frequency amplifier, comprising a first power amplifier, a second power amplifier, a first coupler, a second coupler, a pre-distorted unit and a first quadrature bridge. The first power amplifier carries out power amplification on an initial carrier signal to form an amplified signal; the first quadrature bridge combines the amplified signal with a amplified pre-distorted signal to offset an intermodulation signal to form a combined signal; the first coupler is arranged in front of the first power amplifier to couple the input initial carrier signal; the second coupler is coupled with the combined signal; the pre-distorted unit combines the initial carrier signal from the first coupler and the combined signal from the second coupler to offset to form a pre-distorted signal including the initial carrier signal and the intermodulation signal; and the second power amplifier is used for carrying out the power amplification equivalent to the first power amplifier on the pre-distorted signal to form the amplified pre-distorted signal. The invention realizes higher working bandwidth and working efficiency and can be applied to different working environments.

Description

【Technical field】 [0001] The invention relates to the field of power amplifiers in modern mobile communication systems, in particular to a predistortion radio frequency amplifier. 【technical background】 [0002] For a long time, the efficiency improvement technology and the linearization technology of the power amplifier used in the communication system have been the research hotspots in the industry. [0003] Due to the adoption of various non-constant envelope modulation methods (such as QPSK, QAM, OFDM, etc.), modern wireless communication systems have greatly improved the utilization of frequency resources. , 2.5G, 3G, 4G, LTE) are growing rapidly, and the downlink in the system requires high-efficiency, high-linearity, multi-carrier power amplifiers to amplify to meet the needs of base stations (remote radio frequency unit RRU, repeater, indoor coverage system etc.) coverage requirements of the device. [0004] As is known, the linearization technology of power amplif...

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Problems solved by technology

[0005] Since the non-constant envelope signal of the modulation technology will cause the power amplifier to produce large nonlinear characteristics, the multi-carrier power amplifier conventionally adopts the feed-forward (FF) technology architecture, although it has excellent cancellation performance, wide operating bandwidth, and multi-standard However, due to factors such as high technical complexity, low efficiency, and high cost, its development is restricted

[0006] Due to the influence of factors such as narrow working bandwidth and poor cancellation effect, analog predistortion technologies such as envelope tracking cannot work in the case of multi-carrier

[0007] Digital predistortion technology is a promising linearization technology, which has the characteristics of high work efficiency and moderate cancellation, but due to the limitation of people's understanding of the nonlinear characteristics of semiconductor devices and the limitations of A / D, D / A. Due to the limitation of the working rate of DSP, the working bandwidth is limited, and its application is subject to certain restrictions.

[0008] In addition, no matter from the perspective of theory or practice, domestic and foreign patent documents related to digital pre-distortion technology all reveal that the complexity of generating digital pre-distortion signals in the prior art is relatively high, and it cannot be adaptively adjusted to adapt to different electrical environments. Therefore, a good linearization technique effect cannot be achieved

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