Power Amplifier Harmonic Feedback for Lower Intermodulation Distortion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mobile communication devices face challenges in reducing intermodulation distortion without increasing circuit size, which affects the linearity of power amplifiers when handling signals with adjacent frequencies.
Innovation Solution
A power amplifier circuit design that includes a first amplifier, an extraction circuit to extract the second-harmonic wave, a phase adjustment circuit to adjust its phase, and a power combiner to combine it with the fundamental wave, effectively compensating for intermodulation distortion without requiring additional circuitry for generating a second-harmonic wave.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If an additional amplifier is provided to generate a second-harmonic wave for distortion compensation, then intermodulation distortion is reduced, but circuit size increases
Solution Approach 1:
The first amplifier generates its own second-harmonic wave internally, which is then extracted and fed back to compensate for intermodulation distortion. This self-service approach eliminates the need for a separate second amplifier, reducing circuit size while maintaining distortion compensation effectiveness
Solution Approach 2:
An extraction circuit is introduced as an intermediary component to separate the second-harmonic wave from the amplifier output. This intermediary enables the reuse of the existing amplifier's harmonic content for distortion compensation without requiring additional amplification stages
2Area of stationary object
If the circuit size is reduced by removing additional amplifiers, then device downsizing is achieved, but the ability to compensate for intermodulation distortion is weakened
Solution Approach 1:
The extracted second-harmonic wave is fed back to the input of the first amplifier with adjusted phase and amplitude. This feedback mechanism enables continuous distortion compensation using only the original amplifier, achieving both circuit downsizing and maintained linearity
Solution Approach 2:
The phase and amplitude of the extracted second-harmonic wave are adjusted through dedicated circuits to optimize distortion compensation. By changing these parameters, the system achieves effective intermodulation distortion reduction without requiring additional amplification stages
Data Source
AI summary
Provided is a power amplifier circuit that reduces the effect of intermodulation distortion without necessarily increase in the circuit size. The power amplifier circuit includes a first amplifier that amplifies a first signal and output a second signal, an extraction circuit that extracts a second-harmonic wave included in the second signal, a phase adjustment circuit that adjusts the phase of the extracted second-harmonic wave, and a power combiner that combines the second-harmonic wave of the adjusted phase with a third signal and output the first signal.