Radio-frequency power amplifier circuit with adjustable predistortion function

An amplifier circuit and radio frequency power technology, applied in power amplifiers, improving amplifiers to reduce nonlinear distortion, etc., can solve problems such as changes in the operating point of transistor circuits, and achieve the effect of compensating for changes in ambient temperature and increasing input impedance

CN101888215BActive Publication Date: 2012-09-26SUZHOU INNOTION TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2012-09-26

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    Figure 1
  • Figure 2
    Figure 2
  • Figure 3
    Figure 3
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Abstract

The invention discloses a radio-frequency power amplifier circuit with adjustable predistortion function, comprising a transistor in emitter follower structure; wherein the base electrode of the transistor is connected with the input terminal of the amplifier circuit, the emitter of the transistor is connected with the output terminal of the amplifier circuit by virtue of an output matching network, an RC parallel negative feedback network is connected between the base electrode of the transistor and the collector electrode of the transistor, a first RL series negative feedback network is connected between the collector electrode and an external adjustable bias voltage, and a second RL series negative feedback network is connected between the emitter of the transistor and the ground. Predistortion circuit can be caused to have better accuracy, gain compression and positive phase deviation produced by power amplifier post-stage circuit can be compensated, and linearity thereof can be improved.
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Description

technical field

[0001] The invention relates to a radio frequency power amplifier circuit with adjustable predistortion function. Background technique

[0002] The power amplifier is one of the most nonlinear devices in the communication system, and the linearity of the power amplifier directly affects the performance of the entire communication system. When the input power of the power amplifier is large, its active device parameters (transistor transconductance g m and the base-collector junction capacitance C μ etc.) will change with the input power, causing the power amplifier to enter a nonlinear working state, resulting in two types of nonlinear distortions, gain compression (AM / AM) and phase shift (AM / PM).

[0003] At present, the linearization techniques commonly used in circuit design mainly include: feedforward, feedback, predistortion, digital signal processing predistortion and backward distortion, among which the predistortion technique is the most commonly us...

Examples

Embodiment

[0025] Such as Figure 1a and Figure 1b As shown, the common power amplifier in the prior art will work in a non-linear state as the input power increases, resulting in gain compression and positive phase shift. The greater the input power, the more serious the non-linearity generated by the power amplifier, resulting in greater gain compression and greater positive phase offset.

[0026] Such as figure 2 and image 3 As shown, a radio frequency power amplifier circuit with an adjustable pre-distortion function includes a transistor Q1 of an emitter follower structure, that is, the transistor Q1 is a common-collector transistor, and the base of the transistor Q1 is connected to the input of the amplifier circuit The terminal IN is connected, the emitter of the transistor Q1 is connected with the output terminal OUT of the amplifier circuit through the output matching network 4, and an RC parallel negative feedback network 1 is connected from the base of the transistor Q1 t...