Composite Amplifier Error Cancellation for Wideband Distortion Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrical circuits face significant challenges in reducing distortion, particularly at high frequencies, as distortion increases with frequency, leading to impaired performance in amplifiers, filters, and oscillators due to non-linearities and bias currents, which existing correction methods often exacerbate by requiring significant power and introducing further distortion.
Innovation Solution
A composite amplifier arrangement is introduced, comprising a main amplifier circuit and a compensation amplifier circuit connected to both input and output nodes, utilizing a passive network to isolate and cancel distortion signals, allowing the compensation amplifier to operate on low-level error components and generate compensation signals that reduce total harmonic distortion by up to 50 dB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a correction amplifier operates on both input and output signals to reduce distortion, then distortion reduction is achieved, but the correction amplifier introduces further distortion and requires significant power
Solution Approach 1:
The patent extracts only the error component from the output signal by having the correction amplifier operate exclusively on the difference between input and output signals. This isolation allows the correction amplifier to process only the distortion portion rather than the full signal, reducing its own distortion generation and power requirements while maintaining effective distortion correction.
Solution Approach 2:
The patent introduces an intermediary error signal that represents only the distortion component. This error signal serves as a mediator between the main amplifier output and the correction amplifier input, allowing the correction amplifier to function on a reduced-signal basis that minimizes its own non-linearities and power consumption while still achieving the desired distortion reduction.
2Manufacturing precision
If distortion correction is applied across the entire signal, then comprehensive distortion reduction is achieved, but the correction circuit introduces additional noise and distortion
Solution Approach 1:
The patent extracts only the error component from the output signal by having the correction amplifier operate exclusively on the difference between input and output signals. This isolation allows the correction amplifier to process only the distortion portion rather than the full signal, reducing its own distortion generation and power consumption while maintaining effective distortion correction.
3Manufacturing precision
If high gain is used in the correction amplifier to reduce distortion, then distortion reduction improves, but the correction amplifier's own non-linearities become more significant
Solution Approach 1:
The patent extracts only the error component from the output signal by having the correction amplifier operate exclusively on the difference between input and output signals. This isolation allows the correction amplifier to process only the distortion portion rather than the full signal, reducing its own distortion generation and power consumption while maintaining effective distortion correction.
Data Source
AI summary
A combination amplifier can include a “main amplifier circuit” for signal amplification, and a matching “compensation amplifier circuit” to monitor distortion in the main amplifier output signal. The compensation amplifier circuit provides a compensation signal to the main amplifier circuit to compensate for and servo out distortion therein. The compensation amplifier circuit includes a passive input network and an amplifier. The passive input network can connect to both the input and output nodes of the main amplifier circuit such that the input and output signals cancel within the passive input network, leaving only the low level distortion component introduced in the main amplifier. Thus, the compensation amplifier is then only operating on the low-level distortion introduced in the main amplifier to generate the compensation signal. Because the compensation amplifier is then only operating on the very low distortion signal, any distortion it introduces into the compensation signal is negligible.