RF Amplifier Operating Point Control for Low-EVM Linearity
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Solution Overview
Problem
Radio frequency amplifiers in communication systems face challenges in achieving high linearity and low power consumption, particularly in handheld devices, where substantial non-linear operation leads to unwanted frequencies and high power consumption, affecting battery life and signal quality.
Innovation Solution
A method and device that generate a radio frequency signal based on a baseband signal, using an amplifier with a control circuit to set the operating point by down-converting the amplified signal and comparing it with the baseband signal to adjust the bias voltage and current, ensuring linear operation and minimizing error vector magnitude (EVM) to maintain signal quality and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amplifier operates clearly in the linear area of its current-voltage characteristic, then linearity is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic adjustment of the operating point based on signal conditions. The system continuously monitors the RF signal and adapts the bias voltage and current to maintain optimal linearity only when necessary, rather than operating statically in the linear area. This dynamic approach allows the amplifier to switch between linear and non-linear operating modes, reducing power consumption while maintaining linearity when required.
Solution Approach 2:
The system changes the operating parameters (bias voltage and current) based on the detected signal characteristics. By monitoring the RF signal and adjusting the operating point parameters dynamically, the amplifier can operate in non-linear modes during low-signal conditions and switch to linear modes when signal quality requirements demand it, thus resolving the contradiction between linearity and power consumption.
2Use of energy by moving object
If the amplifier operates in non-linear mode, then power consumption is reduced, but unwanted frequencies and signal distortions increase
Solution Approach 1:
The patent employs a feedback mechanism where the RF signal is monitored and used to adjust the operating point. The system detects signal characteristics and feeds this information back to the control circuit, which then adjusts the bias voltage and current accordingly. This closed-loop feedback ensures that the amplifier operates in non-linear mode (saving power) only when signal conditions permit, and switches to linear mode when distortions or unwanted frequencies become problematic.
Solution Approach 2:
The system dynamically adapts the operating mode based on real-time signal conditions. By continuously monitoring the RF signal and adjusting the operating point accordingly, the amplifier can transition between linear and non-linear operation, reducing power consumption while minimizing harmful distortions through adaptive control.
3Reliability
If the operating point is fixed to ensure linearity, then signal quality is maintained, but adaptability to different signal conditions is reduced
Solution Approach 1:
The patent transforms the fixed operating point into a dynamic, adaptive system. The control circuit continuously monitors RF signal characteristics and adjusts the operating point parameters (voltage and current) in response to changing signal conditions. This allows the amplifier to maintain signal quality when operating in linear mode while adapting to different signal scenarios by switching to non-linear modes when appropriate.
Solution Approach 2:
The system changes the operating parameters dynamically based on detected signal characteristics. By monitoring the RF signal and adjusting bias voltage and current accordingly, the amplifier adapts its operating point to match different signal conditions, thereby maintaining signal quality while improving versatility and energy efficiency.
Data Source
AI summary
Embodiments related to the setting of an operating point of an amplifier are described and depicted.