The Nyquist Criterion: A Useful Tool for the Robust Design of Continuous-Time $\Sigma\Delta$ Modulators

Vuyst, Bart De; Rombouts, Pieter; Maeyer, Jeroen De; Gielen, Georges

doi:10.1109/tcsii.2010.2048368

Cited by 14 publications

(7 citation statements)

References 11 publications

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“…Instead the most demanding layout consideration is with regard to the switches driving the capacitive DAC. Even though the capacitance is not too large, the switch resistance in mode can introduce a pole leading to excess loop delay that could result in performance degradation [36].…”

Section: Measured Resultsmentioning

confidence: 99%

A 0.016 mm2 12 b $\Delta \Sigma $ SAR With 14 fJ/conv. for Ultra Low Power Biosensor Arrays

Leene

Constandinou

2017

IEEE Trans. Circuits Syst. I

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The instrumentation systems for implantable brainmachine interfaces represent one of the most demanding applications for ultra low-power analogue-to-digital-converters (ADC) to date. To address this challenge, this paper proposes a SAR topology for very large sensor arrays that allows an exceptional reduction in silicon footprint by using a continuous time 0-2 MASH topology. This configuration uses a specialized FIR window to decimate the modulator output and reject mismatch errors from the SAR quantizer, which mitigates the overhead from dynamic element matching techniques commonly used to achieve high precision. A fully differential prototype was fabricated using 0.18 μm CMOS to demonstrate 10.8 ENOB precision with a 0.016 mm 2 silicon footprint. Moreover, a 14 fJ/conv figure-of-merit can be achieved, while resolving signals with the maximum input amplitude of ±1.2 Vpp sampled at 200 kS/s. The ADC topology exhibits a number of promising characteristics for both high speed and ultra low-power systems due to the reduced complexity, switching noise, sampling load, and oversampling ratio, which are critical parameters for many sensor applications. Index Terms-A/D conversion, bio-sensors arrays, oversampling, incremental delta-sigma, FIR decimation, low power analogue, ADC calibration. I. INTRODUCTION T HE emergent market for wearable electronics and implantable devices for personalized health care has resulted in a growing demand for miniaturized battery powered systems that wirelessly connect a network of sensors [1]. These systems rely extensively on high precision analogue to digital conversion to leverage digital processing techniques and accommodate stringent diagnostic requirements [2]. As a result the ADC power, area, and precision can have a profound impact on a system's overall capabilities. For this reason oversampling techniques using ADCs have already been used extensively to accommodate the niche characteristics of biomedical devices and acquire low frequency bio-signals [3]. More recent developments allow these techniques to be more applicable to large sensor arrays using an incremental analogue to digital converter (IADC) topology [4]. This is in contrast to the conventional use where a single oversampling ADC continuously converts the signal from a single sensing unit with exceptional efficiency. IADC designs are unique in Manuscript

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Section: Measured Resultsmentioning

confidence: 99%

A 0.016 mm2 12 b $\Delta \Sigma $ SAR With 14 fJ/conv. for Ultra Low Power Biosensor Arrays

Leene

Constandinou

2017

IEEE Trans. Circuits Syst. I

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“…We would also like to point out that with different choices of the noise transfer function, the distribution of the in-band and the out-of-band quantization noises can be different. The loop gain, which determines the out-of-band noise level, must be limited for a stable SDM [10]. The in-band SNR and the loop gain should be compromised in NTF design.…”

Section: System Architecturementioning

confidence: 99%

One-Bit Sigma-Delta Modulator for Nonlinear Visible Light Communication Systems

Qian

Chen

Yao

et al. 2015

IEEE Photon. Technol. Lett.

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In a visible light communication (VLC) system, the modulation bandwidth of light emitting diode (LED) is limited with current technology. In addition, the nonlinearity inherited in the LED prevents the application of spectral efficient modulation schemes with high peak-to-average power ratio (PAPR). These characteristics limit the overall throughput of the VLC system. In this letter, a one-bit sigma-delta modulator (SDM) is introduced to the transmit signal. Such modification is compatible with the current LED lighting systems and LED drivers as the output of the one-bit SDM is equivalent to on-off keying (OOK) signal, thus is immune to system nonlinearities. In addition, the output of the one-bit SDM enjoys high spectral efficiency as the original input signal does. The out-of-band quantization noise can be taken care of at the receiver with analog filtering and digital signal processing. Simulation and experiment results validate that the SDM can significantly improve the VLC system performance.Index Terms-Visible light communications, nonlinearity, Sigma-delta modulator.

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“…As multi-bit quantization is believed to be accurately modeled by a linear gain and additive white noise, most publications on the stability of multi-bit quantizer Δ-Σ modulators are based on this widely accepted model of [16], [18], [19]. In [16] and [17], stability analysis is undertaken to evaluate robustness against circuit non-idealities rather than on the amplitude of the input signal. Although it is shown in [18] that multi-bit quantization is nonlinear and has a limiting overloading level, the accurate prediction of the stability limits of multi-bit quantizer based Δ-Σ modulators still remains unresolved.…”

Section: B Multi-bit Quantizersmentioning

confidence: 99%

Nonlinear Stability Prediction of Multibit Delta–Sigma Modulators for Sinusoidal Inputs

Lota

Al-Janabi

Kale

2014

IEEE Trans. Instrum. Meas.

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The Nyquist Criterion: A Useful Tool for the Robust Design of Continuous-Time $\Sigma\Delta$ Modulators

Cited by 14 publications

References 11 publications

A 0.016 mm2 12 b $\Delta \Sigma $ SAR With 14 fJ/conv. for Ultra Low Power Biosensor Arrays

A 0.016 mm2 12 b $\Delta \Sigma $ SAR With 14 fJ/conv. for Ultra Low Power Biosensor Arrays

One-Bit Sigma-Delta Modulator for Nonlinear Visible Light Communication Systems

Nonlinear Stability Prediction of Multibit Delta–Sigma Modulators for Sinusoidal Inputs

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