Delta Sigma Modulator Comparator Offset Noise Conversion
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Solution Overview
Problem
Delta sigma modulators face challenges in reducing comparator offset noise, which increases with the number of comparators, leading to non-linearities, harmonic distortion, and noise modulation, especially at high frequencies, due to the relative effects of comparator offset voltages and the limited chip area required for increased comparators.
Innovation Solution
A signal processing system that includes a delta sigma modulator with a comparator offset converter, which reroutes reference signals to alter the associations between reference signals and comparator input terminals, converting comparator offsets into additive multi-spectral noise, such as white noise, that can be constructively processed by the modulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of comparators is increased to improve quantization accuracy, then measurement precision is improved, but comparator offset noise increases and chip area increases
Solution Approach 1:
The patent converts the harmful comparator offset voltages into beneficial multi-spectral noise through a noise shaping mechanism. The comparator offset converter processes the offset voltages and transforms them into a noise spectrum that can be filtered by the loop filter, turning the harmful DC offset into filterable AC noise that appears as quantization noise rather than systematic error.
Solution Approach 2:
The patent changes the spectral parameters of comparator offset noise by processing it through the comparator offset converter. This transforms the offset noise from a DC or low-frequency component into multi-spectral noise with energy distributed across multiple frequencies, making it amenable to filtering and reducing its impact on the quantization accuracy.
2Measurement precision
If the number of comparators is increased to improve quantization accuracy, then measurement precision is improved, but chip area increases
Solution Approach 1:
The patent converts the harmful comparator offset voltages into beneficial multi-spectral noise through a noise shaping mechanism. The comparator offset converter processes the offset voltages and transforms them into a noise spectrum that can be filtered by the loop filter, turning the harmful DC offset into filterable AC noise that appears as quantization noise rather than systematic error.
Solution Approach 2:
The patent changes the spectral parameters of comparator offset noise by processing it through the comparator offset converter. This transforms the offset noise from a DC or low-frequency component into multi-spectral noise with energy distributed across multiple frequencies, making it amenable to filtering and reducing its impact on the quantization accuracy.
3Measurement precision
If the number of comparators is increased to improve quantization accuracy, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent converts the harmful comparator offset voltages into beneficial multi-spectral noise through a noise shaping mechanism. The comparator offset converter processes the offset voltages and transforms them into a noise spectrum that can be filtered by the loop filter, turning the harmful DC offset into filterable AC noise that appears as quantization noise rather than systematic error.
Solution Approach 2:
The patent changes the spectral parameters of comparator offset noise by processing it through the comparator offset converter. This transforms the offset noise from a DC or low-frequency component into multi-spectral noise with energy distributed across multiple frequencies, making it amenable to filtering and reducing its impact on the quantization accuracy.
4Manufacturing precision
If comparator offset voltages are reduced to improve linearity, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent converts the harmful comparator offset voltages into beneficial multi-spectral noise through a noise shaping mechanism. The comparator offset converter processes the offset voltages and transforms them into a noise spectrum that can be filtered by the loop filter, turning the harmful DC offset into filterable AC noise that appears as quantization noise rather than systematic error.
Solution Approach 2:
The patent changes the spectral parameters of comparator offset noise by processing it through the comparator offset converter. This transforms the offset noise from a DC or low-frequency component into multi-spectral noise with energy distributed across multiple frequencies, making it amenable to filtering and reducing its impact on the quantization accuracy.
Data Source
AI summary
Quantizers of delta sigma modulators include comparators to quantize a quantizer input signal. Each comparator compares a respective reference signal to the quantizer input signal. A logic processing module determines a quantizer output signal based upon the comparison. During subsequent periods of time, a comparator offset converter alters “reference signal-to-comparator input terminal” associations to reroute respective reference signals from one arrangement of comparator input terminals of at least two (2) of the comparators to a different arrangement of comparator input terminals. The comparator offset converter can randomly alter the reference signal-to-comparator input terminal associations. The comparator offset converter can maintain a 1:1 reference signal-to-comparator input terminal relationship. By maintaining the 1:1 ratio of reference signal-to-comparator input terminal and randomizing the reference signal-to-comparator input terminal associations, the comparator offset converter effectively converts the comparator offset voltage nonlinearities into energies and frequencies that can be constructively processed and improve signal-to-noise ratios.