Auxiliary RF Amplifier Circuit for Harmonic Distortion Cancellation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing radio frequency amplifiers in wireless communication devices often output signals with reduced linearity, experiencing amplitude and phase distortion, especially in normal output power mode and power back-off modes, leading to harmonic and intermodulation distortions.
Innovation Solution
The implementation of an amplifier circuit with auxiliary active circuitry, including a bias resistor and multiple common-source and common-gate amplifiers, which reduces amplitude and phase non-linearity by generating destructive harmonic and intermodulation distortion signals that cancel out existing distortions, thereby improving signal linearity across a range of output powers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional amplifier circuits are used, then the amplifier can provide signal amplification, but the output signals exhibit reduced linearity with distorted amplitude gain and phase
Solution Approach 1:
The amplifier is divided into multiple independent amplifier circuits (first amplifier circuit and second amplifier circuit), each with its own transistor and associated components. This segmentation allows each circuit to be optimized for specific frequency ranges or distortion components, enabling better overall linearity while reducing harmful distortions through distributed processing.
Solution Approach 2:
Multiple amplifier circuits are combined in parallel to produce the final amplified output signal. The circuits work together synergistically, with each contributing to different aspects of signal amplification and distortion cancellation, achieving improved linearity that would be difficult to obtain with a single amplifier circuit.
2Power
If amplifier circuits operate in normal output power mode, then signal amplification is provided, but amplitude and phase distortion increases
Solution Approach 1:
The amplifier circuits are designed to dynamically adjust their operating characteristics based on the input signal conditions. The transistors and associated biasing circuits enable the amplifiers to maintain optimal linearity across varying output power levels, adapting their gain and phase characteristics to compensate for non-linear effects that become more pronounced at higher power levels.
3Power
If amplifier circuits operate in power back-off mode, then output power is reduced, but linearity still deteriorates with harmonic and intermodulation distortions
Solution Approach 1:
The amplifier circuits are designed to generate controlled amounts of harmonic and intermodulation distortion products that are then combined with the main signal path. These distortion products, which would normally be harmful, are actually used to cancel out the unwanted distortions through destructive interference, converting a harmful effect into a beneficial distortion-cancellation mechanism.
Data Source
AI summary
This disclosure is directed to an amplifier with improved linearity compared to other amplifiers. The amplifier may include auxiliary active circuitry to reduce amplitude and/or phase non-linearity of a single-ended or differential common-source amplifier when generating amplified signals. As such, the amplifier may output the amplified signals having an output power across a range of output powers with improved linearity. For example, the amplifier may output the amplified signals with improved linearity when operating at a normal power mode and a power back-off mode. The auxiliary active circuitry may include common-gate amplifiers cross coupled with the common-source amplifiers.