Book•
Understanding Delta-Sigma Data Converters
08 Nov 2004-
TL;DR: This chapter discusses the design and simulation of delta-sigma modulator systems, and some of the considerations for implementation considerations for [Delta][Sigma] ADCs.
Abstract: Chapter 1: Introduction.Chapter 2: The first-order delta-sigma modulator.Chapter 3: The second-order delta-sigma modulator.Chapter 4: Higher-order delta-sigma modulation.Chapter 5: Bandpass and quadrature delta-sigma modulation.Chapter 6: Implementation considerations for [Delta][Sigma] ADCs.Chapter 7: Delta-sigma DACs.Chapter 8: High-level design and simulation.Chapter 9: Example modulator systems.Appendix A: Spectral estimation.Appendix B: The delta-sigma toolbox.Appendix C: Noise in switched-capacitor delta-sigma data converters.
Citations
More filters
01 Jan 2013
TL;DR: In this article, a high-resolution multi-bit delta-sigma ADC implemented in a 0.18 μm CMOS technology is presented for an ADSL Central Office application.
Abstract: A high-resolution multi-bit Delta-Sigma ADC implemented in a 0.18 μm CMOS technology is introduced [47]. The circuit is targeted for an ADSL Central-Office application. An area- and power-efficient realization of a single-loop modulator consisting of a 2nd-order loopfilter and a 3-bit quantizer with an oversampling-ratio of 96 is presented. The delta-sigma modulator features an 85 dB dynamic-range (DR) over a 300 kHz signal bandwidth. The measured power consumption of the ADC core is 15 mW only. An innovative biasing circuitry is introduced for the switched-capacitor integrators. The FOM taking the DR as reference ( 2.7) results in \(1.8~\frac{\mathrm{pJ}}{\mathrm{conv}}\).
Patent•
13 Aug 2020
TL;DR: In this paper, an analog-to-digital converter (ADC) is used to convert an output of the amplifier circuit into a digital value, where each of the plurality of sensor signals is a differential signal and the signal input circuit changes polarity of an output signal according to a first chopping signal.
Abstract: A semiconductor device includes a signal input circuit configured to select one of the plurality of differential sensor signals according to a channel selection signal; an amplifier circuit configured to amplify an output of the signal input circuit; and an analog-to-digital converter (ADC) configured to convert an output of the amplifier circuit into a digital value, wherein each of the plurality of sensor signals is a differential signals and the signal input circuit changes polarity of an output signal thereof according to a first chopping signal, and wherein the ADC includes a delta-sigma modulator configured to generate a bit stream from an output of the amplifier circuit; an output chopping circuit configured to adjust phase of the bit stream according to the first chopping signal; and a filter configured to filter an output of the output chopping circuit and to output the digital value.
01 Jan 2009
TL;DR: The DCIS'09 conference was held at the Universidad de Zaragoza (Unizar) in Spain this article.http://www.unizar.edu.de/
Abstract: Comunicacion presentada al: "DCIS'09" celebrado en Zaragoza y organizado por la Universidad de Zaragoza (Unizar) del 18 al 20 de Noviembre del 2009.
Cites background from "Understanding Delta-Sigma Data Conv..."
...Neither do reference textbooks [8], [9] or studies on non-ideality modeling [10], [11]....
[...]
...In most cases of the CIFB structure (Cascade of Integrators with FeedBack) described in [9] – which is a widely used architecture – the modulator input signal feedforward coefficients are all set to 0 except the first one....
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TL;DR: P87LPC764 has these characters: low power consumption, the internal comparator in the MCU, simple structure with some components and better resolution.
Abstract: The paper introduces the theory of Σ-ΔADC and a method of implementation of Σ-ΔADC with MCU, P87LPC764. It also presents the circuit and program flow chart. P87LPC764 has these characters: low power consumption, the internal comparator in the MCU, simple structure with some components and better resolution.
References
More filters
TL;DR: Higher order modulators are shown not only to greatly reduce oversampling requirements for high-resolution conversion applications, but also to randomize the quantization noise, avoiding the need for dithering.
Abstract: Oversampling interpolative coding has been demonstrated to be an effective technique for high-resolution analog-to-digital (A/D) conversion that is tolerant of process imperfections. A novel topology for constructing stable interpolative modulators of arbitrary order is described. Analysis of this topology shows that with proper design of the modulator coefficients, stability is not a limitation to higher order modulators. Furthermore, complete control over placement of the poles and zeros of the quantization noise response allows treatment of the modulation process as a high-pass filter for quantization noise. Higher order modulators are shown not only to greatly reduce oversampling requirements for high-resolution conversion applications, but also to randomize the quantization noise, avoiding the need for dithering. An experimental fourth-order modulator breadboard demonstrates stability and feasibility, achieving a 90-dB dynamic range over the 20-kHz audio bandwidth with a sampling rate of 2.1 MHz. A generalized simulation software package has been developed to mimic time-domain behavior for oversampling modulators. Circuit design specifications for integrated circuit implementation can be deduced from analysis of simulated data. >
399 citations
TL;DR: It is shown that digital filters comprising cascades of integrate-and-dump functions can match the structure of the noise from sigma delta modulation to provide decimation with negligible loss of signal-to-noise ratio.
Abstract: Decimation is an important component of oversampled analog-to-digital conversion. It transforms the digitally modulated signal from short words occurring at high sampling rate to longer words at the Nyquist rate. Here we are concerned with the initial stage of decimation, where the word rate decreases to about four times the Nyquist rate. We show that digital filters comprising cascades of integrate-and-dump functions can match the structure of the noise from sigma delta modulation to provide decimation with negligible loss of signal-to-noise ratio. Explicit formulas evaluate particular tradeoffs between modulation rate, signal-to-noise ratio, length of digital words, and complexity of the modulating and decimating functions.
342 citations
TL;DR: This paper introduces a new method of analysis for deltasigma modulators based on modeling the nonlinear quantizer with a linearized gain, obtained by minimizing a mean-square-error criterion, followed by an additive noise source representing distortion components.
Abstract: This paper introduces a new method of analysis for deltasigma modulators based on modeling the nonlinear quantizer with a linearized gain, obtained by minimizing a mean-square-error criterion [7], followed by an additive noise source representing distortion components. In the paper, input signal amplitude dependencies of delta-sigma modulator stability and signal-to-noise ratio are analyzed. It is shown that due to the nonlinearity of the quantizer, the signal-to-noise ratio of the modulator may decrease as the input amplitude increases prior to saturation. Also, a stable third-order delta-sigma modulator may become unstable by increasing the input amplitude beyond a certain threshold. Both of these phenomena are explained by the nonlinear analysis of this paper. The analysis is carried out for both dc and sinusoidal excitations.
284 citations
TL;DR: Simple algebraic expressions for this modulation noise and its spectrum in terms of the input amplitude are derived and can be useful for designing oversampled analog to digital converters that use sigma-delta modulation for the primary conversion.
Abstract: When the sampling rate of a sigma-delta modulator far exceeds the frequencies of the input signal, its modulation noise is highly correlated with the amplitude of the input. We derive simple algebraic expressions for this noise and its spectrum in terms of the input amplitude. The results agree with measurements taken on a breadboard circuit. This work can be useful for designing oversampled analog to digital converters that use sigma-delta modulation for the primary conversion.
255 citations
01 Mar 1993
TL;DR: The modulator of a bandpass analog/digital (A/D) converter, with 63 dB signal/noise for broadcast AM bandwidth signals centered at 455 kHz, has been implemented by modifying a commercial digital-audio sigma-delta ( Sigma Delta ) converter.
Abstract: The modulator of a bandpass analog/digital (A/D) converter, with 63 dB signal/noise for broadcast AM bandwidth signals centered at 455 kHz, has been implemented by modifying a commercial digital-audio sigma-delta ( Sigma Delta ) converter. It is the first reported fully monolithic implementation of bandpass noise shaping and has applications to digital radio. >
211 citations