Journal ArticleDOI
A Pulse Frequency Modulation Interpretation of VCOs Enabling VCO-ADC Architectures With Extended Noise Shaping
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TLDR
This paper proposes to study voltage controlled oscillators (VCOs) based on the equivalence with pulse frequency modulators (PFMs) and describes circuit techniques to achieve a good approximation of the required pulse waveforms, which can easily be implemented by practical circuits.Abstract:
In this paper, we propose to study voltage controlled oscillators (VCOs) based on the equivalence with pulse frequency modulators (PFMs). This approach is applied to the analysis of VCO-based analog-to-digital converters (VCO-ADCs) and deviates significantly from the conventional interpretation, where VCO-ADCs have been described as the first-order $\Delta \Sigma $ modulators. A first advantage of our approach is that it unveils systematic error components not described by the equivalence with a conventional $\Delta \Sigma $ modulator. A second advantage is that, by a proper selection of the pulses generated by the PFM, we can theoretically construct an open loop VCO-ADC with an arbitrary noise shaping order. Unfortunately, with the exception of the first-order noise shaping case, the required pulse waveforms cannot easily be implemented on the circuit level. However, we describe circuit techniques to achieve a good approximation of the required pulse waveforms, which can easily be implemented by practical circuits. Finally, our approach enables a straightforward description of multistage $\Delta \Sigma $ modulator architectures, which is an alternative and practically feasible way to realize a VCO-ADC with extended noise shaping.read more
Citations
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Journal ArticleDOI
Time-Encoding Analog-to-Digital Converters: Bridging the Analog Gap to Advanced Digital CMOS-Part 1: Basic Principles
TL;DR: The basic principles of time encoding applied to analog-to-digital converters (ADCs) based on voltage-controlled oscillators (VCOs), one of the most successful time-encoding techniques to date are reviewed.
Journal ArticleDOI
0.04-mm 2 103-dB-A Dynamic Range Second-Order VCO-Based Audio $\Sigma\Delta$ ADC in 0.13- $\mu$ m CMOS
Fernando Cardes,Eric Gutierrez,Andres Quintero,Cesare Buffa,Andreas Wiesbauer,Luis Hernandez +5 more
TL;DR: In this article, a compact area, low power, and highly digital analog-to-digital converter (ADC) for audio applications is presented, which is implemented using only oscillators and digital circuitry, without operational amplifiers nor other highly linear circuits.
Journal ArticleDOI
A Noise-Shaped VCO-Based Nonuniform Sampling ADC With Phase-Domain Level Crossing
Tzu-Fan Wu,Mike Shuo-Wei Chen +1 more
TL;DR: A voltage-controlled oscillator (VCO)-based nonuniform sampling (NUS) analog-to-digital converter (ADC) is introduced, which shifts the conventional voltage-domain level crossing to the phase domain, thus eliminating the need for any continuous-time comparator or reference generator.
Journal ArticleDOI
The Analog Behavior of Pseudo Digital Ring Oscillators Used in VCO ADCs
TL;DR: In this article, the three most relevant pseudo-digital ring oscillator circuits for VCO A/D conversion are modeled by an equivalent 2-terminal diode-like element.
Journal ArticleDOI
Enhanced circuit for linear ring VCO-ADCs
Jonas Borgmans,Pieter Rombouts +1 more
TL;DR: In this paper, a circuit-level technique to improve the bandwidth and noise performance of a linear voltage-controlled ring-oscillator is proposed, where the traditional cross-coupled inverters are modified into feed-forward coupling inverters that pre-charge the subsequent elements in the ring.
References
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Book
Understanding Delta-Sigma Data Converters
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.
Journal ArticleDOI
An analysis of nonlinear behavior in delta - sigma modulators
Sasan H. Ardalan,J.J. Paulos +1 more
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.
Journal ArticleDOI
Analysis and Design of Voltage-Controlled Oscillator Based Analog-to-Digital Converter
TL;DR: In this article, the performance of VCO-based ADCs in the presence of nonidealities such as jitter, nonlinearity, mismatch, and the metastability of D flip-flops is analyzed.
Dissertation
Analysis and design of voltage-controlled oscillator based analog-to-digital converter = 전압조절발진기 기반 아날로그 디지털 변환기의 해석과 설계
Tae-kwang Jang,장태광 +1 more
TL;DR: This paper analyzes the performance of VCO-based ADCs in the presence of nonidealities such as jitter, nonlinearity, mismatch, and the metastability of D flip-flops and design criteria for determining parameters for VCO and digital ADCs are described.
Journal ArticleDOI
Delta-sigma modulators using frequency-modulated intermediate values
TL;DR: In this paper, the first integrator is extracted and implemented by a frequency modulator with the modulating signal as the input, and the result is a simple delta-sigma modulator, allowing straightforward multibit quantization.
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