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 Sep 2015
TL;DR: A resistor string digital-to-analog converter topology employing noise-shaping is presented and the contribution of each noise source in this topology is described in order to specify the necessary parameters to achieve a given resolution.
Abstract: The resolution of precision mechatronic systems employing the best available instrumentation is presently limited by the noise and distortion performance of digital-to-analog converters. The sources of noise and distortion include quantization error, non-linearity, thermal noise, and semiconductor noise. A resistor string digital-to-analog converter topology employing noise-shaping is presented and the contribution of each noise source in this topology is described in order to specify the necessary parameters to achieve a given resolution.
5 citations
23 Aug 2020
TL;DR: This paper proposes a deep video compression method to simultaneously encode multiple frames with Frame-Conv3D and differential modulation and identifies that this technique can make full use of past frames’ information to remove the redundancy between multiple frames, thus achieves better performance.
Abstract: Deep learning (DL) methods have revolutionized the paradigm of computer vision tasks and DL-based video compression is becoming a hot topic. This paper proposes a deep video compression method to simultaneously encode multiple frames with Frame-Conv3D and differential modulation. We first adopt Frame-Conv3D instead of traditional Channel-Conv3D for efficient multi-frame fusion. When generating the binary representation, the multi-frame differential modulation is utilized to alleviate the effect of quantization noise. By analyzing the forward and backward computing flow of the modulator, we identify that this technique can make full use of past frames’ information to remove the redundancy between multiple frames, thus achieves better performance. A dropout scheme combined with the differential modulator is proposed to enable bit rate optimization within a single model. Experimental results show that the proposed approach outperforms the H.264 and H.265 codecs in the region of low bit rate. Compared with recent DL-based methods, our model also achieves competitive performance.
5 citations
TL;DR: A wide DR Σ∆ modulator with chopper-modulated input-scaling-down (CM-ISD) technique has been proposed to deal with large input set while extending dynamic range, showing its potential in advanced non-invasive BCI systems.
5 citations
21 Apr 2008
TL;DR: Focusing on reduction high frequency noise peaks of the output voltage, this paper represents fundamental study of an AC-AC converter and it is indicated that the proposed scheme can reduce output voltage noise peaks.
Abstract: A pair of a converter and an inverter is used for AC to AC power conversion as a usual way. But this method uses two power conversion circuits. This means increasing power conversion stage and leads to large size equipments. Moreover, series connection of power converters results in large conversion losses. On the other hand, direct AC-AC converter can converts AC power to AC power directly. But generally, AC-AC converter needs a complex control technique for generating converter switching pattern. Focusing on reduction high frequency noise peaks of the output voltage, this paper represents fundamental study of an AC-AC converter. The simple configuration is prior and avoiding complexity. The proposed converter uses delta-sigma modulators that are improved to apply to the converter. Comparing to PWM converter, it is indicated that the proposed scheme can reduce output voltage noise peaks.
5 citations
22 Mar 2020
TL;DR: A fully-dynamic, low-power, and wide-band time-interleaved (TI) noise-shaping (NS) SAR ADC based on the cascade of integrators with feed-forward (CIFF) architecture that obviates the need for amplifiers with static current, saving power.
Abstract: This paper presents a fully-dynamic, low-power, and wide-band time-interleaved (TI) noise-shaping (NS) SAR ADC based on the cascade of integrators with feed-forward (CIFF) architecture. Its loop filter and interleaving operation are realized by fully-passive switched capacitor (SC) circuits. Its feedforward summation is implemented by using a multi-path comparator. Moreover, its overall noise transfer function (NTF) is set by device ratios and highly robust against process, voltage, and temperature (PVT) variations. It allows the loop filter poles to be placed close to the unit circle. Comparing to a recently published TI NS SAR ADC based on the error-feedback (EF) structure, this work obviates the need for amplifiers with static current, saving power. It also eliminates the dependence of NTF on the amplifier gain, which is PVT sensitive. A prototype ADC in 40nm process achieves 69.1dB SNDR over 50MHz BW while consuming only 8.5mW from a 1.1V supply, leading to a Walden FoM of 36.3fJ/conv.-step.
5 citations
Cites methods from "Understanding Delta-Sigma Data Conv..."
...To overcome these limitations, this paper proposes a novel TI NS SAR based on the cascade of integrators with feedforward (CIFF) ΔΣ architecture [10]....
[...]
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