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
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Patent•
28 Dec 2010
TL;DR: In this article, a digital audio signal which is input into an acoustic playback system including a digital filter and a plurality of digital modulators each of which output a digital signal to one of the speakers configured with speakers driven by digital signals having different play back bandwidths is provided.
Abstract: An acoustic playback system including a digital filter; and a plurality of digital modulators each of which output a digital signal to one of a plurality of speakers configured with speakers driven by digital signals having different play back bandwidths; wherein the digital filter converts a digital audio signal which is input into a plurality of digital audio signals of a plurality of frequency bandwidths corresponding to play back bandwidths of the plurality of speakers, and outputs each of the digital audio signals of the plurality of frequency bandwidths to one of the plurality of digital modulators; each of the plurality of digital modulators outputs the modulated digital signal to the speaker of a play back bandwidth corresponding to a frequency bandwidth of the digital audio signal which is input by performing miss match shaping after noise shaping to a digital audio signal which is input; and each number of bits of a digital signal which is output by each of the digital modulators is different is provided.
15 citations
05 Nov 2008
TL;DR: In this paper, the effect of the dielectric relaxation on the circuit performance of high resolution sigma-delta ADC has been analyzed for simulation, and it was shown that the noise shaping which is enforced by the integrators in SigmaDelta-ADC is almost not affected by the deformation.
Abstract: Dielectric relaxation of capacitors is one of the error sources when determining the accuracy of analog sampled-data systems that are based on charge storage. To perform an accurate characterization of the dielectric relaxation of metal-insulator-metal (MIM) capacitor, techniques based on the voltage recovery principle and the Curie Von Schweidler discharge current approach are developed. To model the dielectric relaxation of the MIM capacitor, Dow's model is selected. An algorithm for the model parameter extraction on the Curie Von Schweidler current has been developed, which shows the phenomenon of dielectric relaxation in detail and is very fast to determine the parameters. Based on the measurement data, a set of model parameters is extracted and verified, which approximates the Curie Von Schweidler law over a sufficiently wide interval of time constants. To study the effect of the dielectric relaxation on the circuit performance of high resolution sigma-delta ADC, a 12-b incremental ADC has been selected as an example for simulation. The simulation results show that the effect of the dielectric relaxation on the performance of the 12-b ADC is not significant. We show that the .major reason for this is that the noise shaping which is enforced by the integrators in SigmaDelta-ADC is almost not affected by the dielectric relaxation phenomenon.
15 citations
19 Dec 2011
TL;DR: A new architecture of analog to information converter that produces 1-bit compressive measurements and the effectiveness of the architecture and of its enhancement is shown in the measurement of EEG, that presents a non-uniform spectral profile.
Abstract: Compressed sensing exploits special signal features to extract its information content with a smaller amount of samples with respect to acquisition based on Nyquist theorem. While many theoretical results have proved the capabilities of this new paradigm, hardware implementations are still far from being practical. Here, we present a new architecture of analog to information converter that produces 1-bit compressive measurements. The performance of the architecture can be boosted if the signal to acquire features, beyond the classically required sparsity, also some sort of localization of its energy. The effectiveness of the architecture and of its enhancement is shown in the measurement of EEG, that presents a non-uniform spectral profile.
15 citations
Cites background from "Understanding Delta-Sigma Data Conv..."
...The discrete-time implementation of the circuit is inherently more accurate than its analog counterparts [6]....
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01 Jan 2007
TL;DR: In this paper, an enhanced version of Sturdy MASH (SMASH) (2) delta-sigma modulator is proposed, which takes advantage of the well-known stability of the MASH structure while greatly reducing its sensitivity to imperfect circuit blocks.
Abstract: An enhanced version of Sturdy MASH (SMASH) (2) delta-sigma modulator is proposed. This structure takes advantage of the well-known stability of the MASH structure while greatly reducing its sensitivity to imperfect circuit blocks. Furthermore, no digital noise cancellation filters are needed. Hence there is no matching requirement for the analog and digital paths. With the proposed enhancement in noise shaping, the first and second stage quantization noise experience different (thus mixed) orders of noise shaping, and the accuracy of this modulator is comparable of that of the MASH structure. Simulations results and mathematical analysis demonstrate the effectiveness of this structure. Delta-Sigma modulators (DSMs) are mostly used in high- accuracy, low-to-medium bandwidth applications, benefiting from oversampled operation. Oversampling allows achieving high accuracy without necessarily using accurate circuit elements. This, however, comes at the cost of a higher sampling frequency. For wide-band applications, the sampling frequency may need to be over 200 MHz to satisfy the required SNR. This may require large bias power for the amplifiers in the modulator, and the speed of the amplifiers may exceed the transit frequency of the given technology. To decrease this high sampling frequency, while maintaining the
15 citations
TL;DR: This paper analytically derive a solution to the problem of designing decentralized sigma-delta modulators for quantized control such that the resulting quantized feedback system optimally approximates the corresponding unquantized system.
Abstract: This paper addresses a problem of designing decentralized sigma-delta modulators for quantized control, i.e., feedback control subject to quantized signal constraints. The sigma-delta modulators to be considered here have a limited information structure so as to be implemented in a decentralized manner, which poses a challenging design problem. We first analytically derive a solution to the problem such that the resulting quantized feedback system optimally approximates the corresponding unquantized system. Next, the performance is demonstrated by a numerical simulation and an experiment for the stabilization problem of a seesaw-cart system.
15 citations
References
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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