Dual-ADC Receiving Circuit for Harmonic Distortion Cancellation
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Solution Overview
Problem
Operational amplifiers in analog circuits, such as ADCs, experience harmonic distortion when input signals exceed a certain strength, leading to degraded signal quality due to non-linear operation.
Innovation Solution
A receiving circuit comprising a first ADC, an attenuator, a second ADC, and a harmonic generation circuit, which reduces signal strength and generates harmonic signals to delete harmonic components from the output, ensuring the second digital signal operates within the linear region and allows for effective harmonic distortion reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the input signal strength is increased to improve signal quality, then the signal quality deteriorates due to non-linear operation and harmonic distortion
Solution Approach 1:
The patent segments the signal processing into multiple paths: a first ADC processes the full-strength signal, while a second ADC processes an attenuated version of the same signal. This segmentation allows the system to handle strong signals without distortion by comparing against a known attenuated reference, effectively resolving the contradiction between maintaining signal quality and avoiding harmonic distortion.
Solution Approach 2:
The attenuated signal path acts as an intermediary reference that does not suffer from non-linear distortion. By using this undistorted attenuated signal as a reference for correction, the system can eliminate harmonic components from the main signal path without losing the original signal strength, thus resolving the contradiction between signal quality and harmonic distortion.
2Reliability
If the input signal strength is reduced to avoid non-linear operation, then the signal strength decreases requiring additional processing
Solution Approach 1:
The attenuated signal serves multiple functions: it acts as a reference for harmonic cancellation, provides a linear operating point for the second ADC, and enables correction of the main signal path. This multi-functionality justifies the additional circuit complexity by providing reliable linear operation and harmonic distortion reduction simultaneously.
3Measurement precision
If multiple ADCs are used to reduce harmonic distortion, then the harmonic distortion is reduced but the device complexity increases
Solution Approach 1:
The patent extracts the harmonic distortion components by comparing the full-strength signal path with the attenuated signal path. By taking out and identifying the harmonic components present in the main path but not in the attenuated reference path, the system can selectively remove these harmful components while preserving the useful signal, thus improving output accuracy despite increased component count.
Data Source
AI summary
The present invention provides a receiving circuit, wherein the receiving circuit includes a first ADC, an attenuator, a second ADC, a harmonic generation circuit and an output circuit. In the operations of the receiving circuit, the first ADC performs an analog-to-digital operation on an analog input signal to generate a first digital output signal, the attenuator reduces strength of the analog input signal to generate an attenuated analog input signal, the second ADC performs the analog-to-digital operation on the attenuated analog input signal to generate a second digital input signal, the harmonic generation circuit generates at least one harmonic signal according to the second digital input signal, and the output circuit deletes a harmonic component of the first digital input signal by using the at least one harmonic signal to generate an output signal.