IEICE TRANSACTIONS on Fundamentals
Novel Architecture of Feedforward Second-Order Multibit ΔΣAD Modulator
Summary :
This paper proposes novel feedforward architecture of the second-order multibit ΔΣAD modulator with single DAC-feedback topology. The ΔΣAD modulator realizes high resolution by oversampling and noise shaping techniques. However, its SNDR (Signal to Noise and Distortion Ratio) is limited by the dynamic range of the input signal and non-idealities of circuit building blocks, particularly by the harmonic distortion in amplifier circuits. A full feedforward ΔΣAD modulator structure has the signal transfer function of unity under ideal circumstances, which means that the signal swings through the loop filter become smaller compared with a feedbacked ΔΣAD modulator. Therefore, the harmonic distortion generated inside the loop filter can be significantly reduced in the feedforward structure because the effect of non-idealities in amplifiers can be suppressed when signal swing is small. Moreover, the reduction of the internal signal swings also relaxes output swing requirements for amplifiers with low supply voltage. However, in conventional feedforward ΔΣAD modulator, an analog adder is needed before quantizer, and especially in a multibit modulator, an additional amplifier is necessary to realize the summation of feedforward signals, which leads to extra chip area and power dissipation. In this paper, we propose a novel architecture of a feedforward ΔΣAD modulator which realizes the summation of feedforward signals without additional amplifier. The proposed architecture is functionally equivalent to the conventional one but with smaller chip area and lower power dissipation. We conducted MATLAB and SPICE simulations to validate the proposed architecture and modulator circuits.
- Publication
- IEICE TRANSACTIONS on Fundamentals Vol.E91-A No.4 pp.965-970
- Publication Date
- 2008/04/01
- Publicized
- Online ISSN
- 1745-1337
- DOI
- 10.1093/ietfec/e91-a.4.965
- Type of Manuscript
- Special Section PAPER (Special Section on Selected Papers from the 20th Workshop on Circuits and Systems in Karuizawa)
- Category
Authors
Hao SAN
Hajime KONAGAYA
Feng XU
Atsushi MOTOZAWA
Haruo KOBAYASHI
Kazumasa ANDO
Hiroshi YOSHIDA
Chieto MURAYAMA
Kanichi MIYAZAWA
Keyword
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Hao SAN, Hajime KONAGAYA, Feng XU, Atsushi MOTOZAWA, Haruo KOBAYASHI, Kazumasa ANDO, Hiroshi YOSHIDA, Chieto MURAYAMA, Kanichi MIYAZAWA, "Novel Architecture of Feedforward Second-Order Multibit ΔΣAD Modulator" in IEICE TRANSACTIONS on Fundamentals,
vol. E91-A, no. 4, pp. 965-970, April 2008, doi: 10.1093/ietfec/e91-a.4.965.
Abstract: This paper proposes novel feedforward architecture of the second-order multibit ΔΣAD modulator with single DAC-feedback topology. The ΔΣAD modulator realizes high resolution by oversampling and noise shaping techniques. However, its SNDR (Signal to Noise and Distortion Ratio) is limited by the dynamic range of the input signal and non-idealities of circuit building blocks, particularly by the harmonic distortion in amplifier circuits. A full feedforward ΔΣAD modulator structure has the signal transfer function of unity under ideal circumstances, which means that the signal swings through the loop filter become smaller compared with a feedbacked ΔΣAD modulator. Therefore, the harmonic distortion generated inside the loop filter can be significantly reduced in the feedforward structure because the effect of non-idealities in amplifiers can be suppressed when signal swing is small. Moreover, the reduction of the internal signal swings also relaxes output swing requirements for amplifiers with low supply voltage. However, in conventional feedforward ΔΣAD modulator, an analog adder is needed before quantizer, and especially in a multibit modulator, an additional amplifier is necessary to realize the summation of feedforward signals, which leads to extra chip area and power dissipation. In this paper, we propose a novel architecture of a feedforward ΔΣAD modulator which realizes the summation of feedforward signals without additional amplifier. The proposed architecture is functionally equivalent to the conventional one but with smaller chip area and lower power dissipation. We conducted MATLAB and SPICE simulations to validate the proposed architecture and modulator circuits.
URL: https://global.ieice.org/en_transactions/fundamentals/10.1093/ietfec/e91-a.4.965/_p
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@ARTICLE{e91-a_4_965,
author={Hao SAN, Hajime KONAGAYA, Feng XU, Atsushi MOTOZAWA, Haruo KOBAYASHI, Kazumasa ANDO, Hiroshi YOSHIDA, Chieto MURAYAMA, Kanichi MIYAZAWA, },
journal={IEICE TRANSACTIONS on Fundamentals},
title={Novel Architecture of Feedforward Second-Order Multibit ΔΣAD Modulator},
year={2008},
volume={E91-A},
number={4},
pages={965-970},
abstract={This paper proposes novel feedforward architecture of the second-order multibit ΔΣAD modulator with single DAC-feedback topology. The ΔΣAD modulator realizes high resolution by oversampling and noise shaping techniques. However, its SNDR (Signal to Noise and Distortion Ratio) is limited by the dynamic range of the input signal and non-idealities of circuit building blocks, particularly by the harmonic distortion in amplifier circuits. A full feedforward ΔΣAD modulator structure has the signal transfer function of unity under ideal circumstances, which means that the signal swings through the loop filter become smaller compared with a feedbacked ΔΣAD modulator. Therefore, the harmonic distortion generated inside the loop filter can be significantly reduced in the feedforward structure because the effect of non-idealities in amplifiers can be suppressed when signal swing is small. Moreover, the reduction of the internal signal swings also relaxes output swing requirements for amplifiers with low supply voltage. However, in conventional feedforward ΔΣAD modulator, an analog adder is needed before quantizer, and especially in a multibit modulator, an additional amplifier is necessary to realize the summation of feedforward signals, which leads to extra chip area and power dissipation. In this paper, we propose a novel architecture of a feedforward ΔΣAD modulator which realizes the summation of feedforward signals without additional amplifier. The proposed architecture is functionally equivalent to the conventional one but with smaller chip area and lower power dissipation. We conducted MATLAB and SPICE simulations to validate the proposed architecture and modulator circuits.},
keywords={},
doi={10.1093/ietfec/e91-a.4.965},
ISSN={1745-1337},
month={April},}
Copy
TY - JOUR
TI - Novel Architecture of Feedforward Second-Order Multibit ΔΣAD Modulator
T2 - IEICE TRANSACTIONS on Fundamentals
SP - 965
EP - 970
AU - Hao SAN
AU - Hajime KONAGAYA
AU - Feng XU
AU - Atsushi MOTOZAWA
AU - Haruo KOBAYASHI
AU - Kazumasa ANDO
AU - Hiroshi YOSHIDA
AU - Chieto MURAYAMA
AU - Kanichi MIYAZAWA
PY - 2008
DO - 10.1093/ietfec/e91-a.4.965
JO - IEICE TRANSACTIONS on Fundamentals
SN - 1745-1337
VL - E91-A
IS - 4
JA - IEICE TRANSACTIONS on Fundamentals
Y1 - April 2008
AB - This paper proposes novel feedforward architecture of the second-order multibit ΔΣAD modulator with single DAC-feedback topology. The ΔΣAD modulator realizes high resolution by oversampling and noise shaping techniques. However, its SNDR (Signal to Noise and Distortion Ratio) is limited by the dynamic range of the input signal and non-idealities of circuit building blocks, particularly by the harmonic distortion in amplifier circuits. A full feedforward ΔΣAD modulator structure has the signal transfer function of unity under ideal circumstances, which means that the signal swings through the loop filter become smaller compared with a feedbacked ΔΣAD modulator. Therefore, the harmonic distortion generated inside the loop filter can be significantly reduced in the feedforward structure because the effect of non-idealities in amplifiers can be suppressed when signal swing is small. Moreover, the reduction of the internal signal swings also relaxes output swing requirements for amplifiers with low supply voltage. However, in conventional feedforward ΔΣAD modulator, an analog adder is needed before quantizer, and especially in a multibit modulator, an additional amplifier is necessary to realize the summation of feedforward signals, which leads to extra chip area and power dissipation. In this paper, we propose a novel architecture of a feedforward ΔΣAD modulator which realizes the summation of feedforward signals without additional amplifier. The proposed architecture is functionally equivalent to the conventional one but with smaller chip area and lower power dissipation. We conducted MATLAB and SPICE simulations to validate the proposed architecture and modulator circuits.
ER -
English
