Doherty Amplifier Amplitude-Phase Control for Distortion Adaptation
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Solution Overview
Problem
Existing distortion compensating circuits in amplifiers struggle to reduce distortion in output signals when the non-linear characteristic of the amplifier changes due to factors like temperature variations or deterioration over time, as they rely on fixed compensation coefficients that may not accurately represent the amplifier's inverse characteristic.
Innovation Solution
An amplitude and phase control device that dynamically adjusts the amplitude and phase of signals output to a Doherty amplifier using a distortion compensating unit, error calculating unit, and controlling unit, which calculates and applies appropriate compensation coefficients to maintain effective distortion reduction even when the amplifier's non-linear characteristic changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fixed compensation coefficients are used in the distortion compensating circuit, then the device complexity is reduced and ease of manufacture is improved, but the reliability deteriorates when the non-linear characteristic of the amplifier changes due to temperature variations or deterioration over time
Solution Approach 1:
The patent applies the dynamics principle by transitioning from fixed compensation coefficients to dynamically adjustable coefficients. The distortion compensating circuit now includes a compensation coefficient adjusting unit that can modify the coefficients based on detected changes in the amplifier's non-linear characteristics, allowing the system to adapt to temperature variations and deterioration over time while maintaining reliable distortion compensation
Solution Approach 2:
The patent implements parameter changes by modifying the compensation coefficients a_k,q based on detected changes in amplifier characteristics. The system detects changes in non-linear characteristics and adjusts the parameters (compensation coefficients) accordingly, enabling the distortion compensating circuit to maintain effectiveness under varying operating conditions without requiring complete redesign
2Manufacturing precision
If the number of compensation coefficients is increased to improve distortion compensation accuracy, then the manufacturing precision and reliability are improved, but the device complexity increases
Solution Approach 1:
The patent applies dynamics by making the compensation coefficient system adjustable rather than static. Instead of permanently increasing the number of coefficients, the system dynamically adjusts the existing coefficients based on detected changes in amplifier characteristics, achieving improved compensation accuracy without proportionally increasing device complexity
Solution Approach 2:
The patent implements self-service through the compensation coefficient adjusting unit that automatically detects changes in amplifier non-linear characteristics and adjusts the compensation coefficients accordingly. This self-adjusting mechanism improves manufacturing precision without requiring external intervention or complex manual calibration procedures
Data Source
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AI summary
An amplitude and phase control device (10) is provided with a signal dividing unit (12) to divide a transmission signal into a first signal and a second signal and output each of the first signal and the second signal to a Doherty amplifier (14), an error calculating unit (16) to acquire, from the Doherty amplifier (14), a synthesized signal of a first signal amplified by the Doherty amplifier (14) and a second signal amplified by the Doherty amplifier (14), multiply the synthesized signal by a reciprocal of a gain of the Doherty amplifier (14), and calculate an error between a synthesized signal after being multiplied by the reciprocal and the transmission signal, and a controlling unit (17) to control an amplitude of each of the first signal and the second signal output from the signal dividing unit (12) depending on the error calculated by the error calculating unit (16), and control a phase difference between the first signal output from the signal dividing unit (12) and the second signal output from the signal dividing unit (12) depending on the error.