Radio-frequency power amplifier circuit with adjustable predistortion function

A technology for amplifier circuits and radio frequency power, applied in power amplifiers, improved amplifiers to reduce nonlinear distortion, etc., can solve problems such as changes in transistor circuit operating points, and achieve the effects of compensating for environmental temperature changes and increasing input impedance

CN101888215AActive Publication Date: 2010-11-17SUZHOU INNOTION TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2010-11-17

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    Figure 1
  • Figure 2
    Figure 2
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    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 an adjustable predistortion function. Background technique

[0002] The power amplifier is one of the most non-linear devices in the communication system. 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 (transconductance of the transistor g m And base-collector junction capacitance C μ Etc.) will change with the input power, causing the power amplifier to enter a non-linear working state, resulting in gain compression (AM / AM) and phase shift (AM / PM) two types of non-linear distortion.

[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 predistortion technology is the most commonly used and si...

Examples

Embodiment

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

[0026] Such as figure 2 with image 3 As shown, a radio frequency power amplifier circuit with adjustable predistortion function includes a transistor Q1 with 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 Terminal IN is connected, the emitter of the transistor Q1 is connected to 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 to the collector of the transisto...