Delta-Sigma ADC Kickback Filter for Low Oversampling Noise
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Solution Overview
Problem
Analog to digital conversion systems, particularly those using Delta-Sigma Modulators, face challenges in low oversampling ratios due to non-linearities caused by manufacturing variations and circuit imperfections, leading to noise issues that render them unreliable at lower bandwidths.
Innovation Solution
The implementation of a kickback filter, such as a buffer or band pass filter, is introduced to reduce or eliminate noise that can feedback onto the input signal, allowing the system to operate effectively at higher frequencies and lower oversampling rates by electrically coupling the input signal to summation elements via this filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Delta-Sigma Modulator is used for analog to digital conversion, then high oversampling ratios achieve desired signal to noise ratio and linear performance, but the system does not work well at low oversampling ratios due to non-linearities caused by manufacturing variations and circuit imperfections
Solution Approach 1:
A kickback filter is introduced as an intermediary component between the second integrator and the second summation element. This filter blocks noise generated at the second summation element from feeding back to the input signal, thereby enabling reliable operation at low oversampling ratios while maintaining good signal to noise ratio performance
2Measurement precision
If the circuit is used at relatively high oversampling rates, then the level of noise is reduced, but the circuit becomes unreliable at lower oversampling rates due to noise at or near the band of interest
Solution Approach 1:
The harmful noise feedback path is extracted and removed from the system by introducing a kickback filter. This filter specifically targets and eliminates the noise feedback mechanism that causes unreliability at low oversampling rates, allowing the system to operate effectively across a wider range of oversampling ratios
3Manufacturing precision
If high quality analog components are used to address non-linearities, then some causes of non-linearities are mitigated, but the system is still generally not capable of adequate operation at low oversampling rates
Solution Approach 1:
Rather than relying solely on high quality analog components, a kickback filter is introduced as an intermediary mechanism that actively prevents noise feedback. This approach addresses the fundamental noise feedback issue that high quality components alone cannot resolve, enabling reliable operation at low oversampling rates
Data Source
AI summary
Various systems and methods for analog to digital conversion are disclosed. For example, some embodiments of the present invention provide analog to digital conversion systems. The analog to digital conversion systems include a first integrator and a second integrator, and a first summation element and a second summation element. An output of the first summation element is electrically coupled to the first integrator, and an output of the first integrator is electrically coupled to the second integrator. An output of the second integrator is electrically coupled to the second summation element. The analog to digital conversion systems further include an analog to digital converter that is electrically coupled to the first summation element via a digital to analog converter. An input to the analog to digital conversion system is electrically coupled to the first summation element, and the input is electrically coupled to the second summation element via a kickback filter.