Adaptive Multi-Bit Sigma-Delta ADC for Rapid Pulse Transients

Solution Overview

Problem

Single-bit sigma-delta modulation struggles to accurately capture the shape of waveforms with rapid transients, such as pulses, due to its inability to keep up with the analog waveform, leading to signal overload and loss of waveform shape information.

Innovation Solution

A multi-bit sigma-delta modulator is introduced, featuring a summation circuit, integrator, multi-bit quantizer, and negative feedback circuit with a non-linear relationship between digital output signals and analog feedback, allowing for more than two levels of quantization and optimized quantization levels to match the temporal properties of the analog input signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If single-bit sigma-delta modulation is used to digitize analog signals, then power consumption is low and component count is minimal, but the converter cannot keep up with rapid transients causing waveform shape information to be lost

Engineering Contradiction:

Improvesampling rateVSAvoidwaveform shape information

Core Design Contradiction:

SpeedVSLoss of information

Solution Approach 1:

The patent changes the quantization parameter from 1-bit to multi-bit (N-bit), enabling the system to represent multiple amplitude levels simultaneously. This allows the converter to track rapid transients in the analog waveform while maintaining the oversampling architecture's benefits, thus preserving waveform shape information without proportionally increasing power consumption or component complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces adaptive sampling rate adjustment that dynamically changes the sampling frequency based on the characteristics of the input signal. For signals with rapid transients, the sampling rate increases to capture waveform shape information, while for slower signals, the rate decreases to maintain low power consumption, making the system responsive to actual signal demands

Inventive Principle:

Principle #15Dynamics

2Loss of information

If sampling rate is increased to capture rapid transients, then waveform shape information is preserved, but power consumption and component complexity increase

Engineering Contradiction:

Improvewaveform shape informationVSAvoidpower consumption

Core Design Contradiction:

Loss of informationVSUse of energy by moving object

Solution Approach 1:

The patent changes the quantization parameter from 1-bit to multi-bit (N-bit), enabling the system to represent multiple amplitude levels simultaneously. This allows the converter to track rapid transients in the analog waveform while maintaining the oversampling architecture's benefits, thus preserving waveform shape information without proportionally increasing power consumption or component complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies partial action by using multi-bit quantization only when needed for rapid transients, rather than continuously operating at maximum sampling rate. The adaptive nature of the system allows it to use higher resolution and sampling rates selectively, reducing overall power consumption while maintaining waveform shape information when required

Inventive Principle:

Principle #16Partial or excessive action

3Measurement precision

If multi-bit quantization is used to preserve waveform shape, then measurement precision improves, but device complexity increases

Engineering Contradiction:

Improvewaveform shape measurementVSAvoidconverter complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the quantization parameter from 1-bit to multi-bit (N-bit), enabling the system to represent multiple amplitude levels simultaneously. This allows the converter to track rapid transients in the analog waveform while maintaining the oversampling architecture's benefits, thus preserving waveform shape information without proportionally increasing power consumption or component complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent designs the multi-bit sigma-delta modulator to serve multiple functions: it captures waveform shape information through multi-bit quantization, maintains compatibility with existing oversampling architectures, and provides adaptive sampling rate adjustment. This multi-functionality allows the system to achieve improved measurement precision without proportionally increasing device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11115045B2Adaptive analog-to-digital converter for pulsed signals based on multi-bit sigma-delta modulation

Publication Date: 2021.09.07 THE ARIZONA BOARD OF REGENTS ON BEHALF OF THE UNIV OF ARIZONA

AI summary

A delta sigma modulator includes a summation circuit, at least one integrator, a multi-bit quantizer and a negative feedback circuit. The summation circuit is configured to produce a difference signal between an analog input signal and an analog feedback signal. The integrator is operatively coupled to the summation circuit to integrate the difference signal. The multi-bit quantizer is operatively coupled to the integrator to digitize the integrated signal to generate an N-bit digital output signal, N being an integer greater than 1. The negative feedback circuit operatively couples the multi-bit quantizer to the summation circuit. The negative feedback circuit includes a digital-to-analog converter arrangement for receiving the N-bit digital output signal and providing the analog feedback signal such that digital values of the N-bit digital output signal and values of the analog feedback encoded by the digital values have a non-linear relationship to one another.