Feedback Calibration Mechanism for RF Signal Linearity
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Solution Overview
Problem
In communication apparatuses, the amplified RF signals often suffer from distortion due to the lack of efficient calibration mechanisms, leading to reduced output linearity of the power amplifier circuit.
Innovation Solution
A communication apparatus with a feedback calibration mechanism that includes a signal transmission circuit, a signal amplifying circuit, an LC impedance matching circuit, and a feedback calibration circuit, where a feedback inductive circuit filters harmonic tones from the amplified signal to generate a feedback signal, allowing the calibration circuit to modify operation parameters and improve linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a power amplifier circuit amplifies RF signals, then signal transmission capability is improved, but distortion occurs and output linearity deteriorates
Solution Approach 1:
The patent implements a feedback calibration mechanism where a feedback inductive circuit samples the amplified analog signal from the power amplifier circuit and feeds it back to a calibration circuit. The calibration circuit compares the feedback signal with the original RF analog signal, detects distortion, and adjusts the operation parameters of the power amplifier circuit to minimize distortion and improve output linearity.
Solution Approach 2:
The patent introduces an LC impedance matching circuit with inductive coupling as an intermediary between the power amplifier circuit and the antenna. This intermediary structure enables efficient signal transmission while providing a controlled environment for feedback sampling, allowing the system to maintain both high power output and good linearity through the feedback mechanism.
2Manufacturing precision
If feedback calibration mechanism is added, then output linearity is improved, but device complexity increases
Solution Approach 1:
The feedback inductive circuit serves multiple functions: it provides impedance matching between stages, samples the amplified signal for feedback, and enables distortion detection. By making this component multi-functional, the patent reduces the need for separate dedicated components, thereby limiting the increase in device complexity while still achieving improved linearity through feedback calibration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The feedback calibration mechanism effectively reduces harmonic tones in the feedback signal, enhancing the accuracy of calibration and increasing the output linearity of the signal amplifying circuit.
Implementation Method 1
The feedback inductive circuit is configured to inductively couple to the LC impedance matching circuit to receive the amplified analog signal
Data Source
AI summary
The present invention discloses a communication apparatus having feedback calibration mechanism. A signal transmission circuit generates a RF analog signal according to a digital signal. A signal amplifying circuit amplifies the RF analog signal to generate an amplified analog signal. A LC impedance matching circuit transmits the amplified analog signal to the antenna to perform transmission. A feedback calibration circuit includes a feedback inductive circuit and a calibration circuit. A feedback inductive circuit is inductively coupled to the LC impedance matching circuit to receive the amplified analog signal to generate a feedback signal. A calibration circuit determines a distorted amount of the feedback signal relative to the RF analog signal to modify an operation parameter of at least one of the signal transmission circuit and the signal amplifying circuit to decrease the distorted amount.