Series Amplifier Inversion for Wideband Second-Order Distortion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wideband communication systems face challenges in reducing second-order non-linear distortion, as conventional methods require additional amplifiers in parallel configurations, which are not always feasible or convenient.
Innovation Solution
A series configuration of non-linear and linear circuit stages is employed, where the first non-linear stage processes the signal, followed by a linear stage that inverts and attenuates it, and then a second non-linear stage further processes the signal, resulting in overall unity gain and cancellation of second-order distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If multiple amplifiers are arranged in parallel balanced configuration to reduce second order distortion, then second order harmonic distortion is reduced, but device complexity increases and additional amplifiers are required
Solution Approach 1:
The patent inverts the conventional parallel configuration by using a series arrangement of amplifiers. The second amplifier is configured to provide signal inversion, and through careful gain matching between stages, the second order distortion products generated by the first amplifier are cancelled at the output. This series inversion approach achieves distortion reduction without requiring parallel amplifier paths.
Solution Approach 2:
The patent changes the operational parameters of the amplifiers, specifically adjusting the gain of each stage and the inversion characteristics of the second amplifier. By matching the gain parameters and inversion depth between stages, the distortion cancellation is optimized. This parameter tuning allows distortion reduction using standard series-connected amplifiers rather than requiring complex parallel configurations.
2Object-generated harmful factors
If filtering is used to remove second order distortion in narrow-band systems, then distortion is reduced, but this method is inappropriate for wideband systems where instantaneous bandwidth exceeds an octave
Solution Approach 1:
The patent converts the harmful second order distortion products into a useful cancellation mechanism. By intentionally allowing the first amplifier to generate distortion and then using the second inverting amplifier to create equal but opposite distortion products, the harmful effect is transformed into a beneficial cancellation effect. This approach works effectively for wideband signals where filtering would be impractical.
3Object-generated harmful factors
If a parallel path for amplifiers is used to reduce second order distortion, then distortion cancellation is achieved, but this solution is not always possible or convenient
Solution Approach 1:
The patent merges the distortion reduction function into the existing series amplifier chain by adding signal inversion capability to the second amplifier stage. Rather than creating a separate parallel path, the inversion and cancellation functions are integrated into the sequential signal flow. This merging approach simplifies implementation and makes the solution more manufacturable and deployable in practical systems.
Data Source
AI summary
A system has a plurality of non-linear circuit stages and an intervening linear circuit stage. An input signal is provided to a first non-linear circuit stage, and from the first non-linear circuit stage, to the linear circuit stage. The first non-linear circuit stage applies a second-order distortion to the input signal and provides the resulting signal to the linear circuit stage. The resulting signal that is output from the linear circuit stage is inverted with respect to the input signal and suitably linearly processed (attenuated or amplified). This signal is then provided to a second non-linear circuit that applies a second-order distortion and outputs a signal that has an overall reduction in second-order distortion.