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Yong-Ping?XuEmail author Xiaofeng?Wang Wai?Hoong?Sun 《Analog Integrated Circuits and Signal Processing》2005,44(3):261-269
This paper describes an initial work on a second-order bandpass Sigma-delta modulator employing crystal resonator. The aim
of this work is to explore the possibilities of realizing bandpass sigma-delta modulator using non-electronic resonators,
such as micro-mechanical resonators. The initial study is based on crystal resonators as they have similar characteristics
as the other types of resonator and are readily available. In order to obtain the desired loop transfer function, a compensation
circuit is proposed to cancel the anti-resonance in the crystal resonator. The modulator chip is fabricated in a 0.6-μ m CMOS
process. The bandpass noise shaping is demonstrated in the experiment with a 1- and 8-MHz crystal resonator, respectively.
Yong Ping Xu graduated from Nanjing University, P.R. China in 1977. He received his Ph.D. from University of New South Wales (UNSW) Australia,
in 1994. From 1978 to 1987, he was with Qingdao Semiconductor Research Institute, P.R.China, initially as an IC design engineer,
and later the deputy R&D manager and the Director. From 1993 to 1995, he worked on an industry collaboration project with
GEC Marconi, Sydney, Australia, at the same university, involved in design of sigma-delta ADCs. He was a lecturer at University
of South Australia, Adelaide, Australia from 1996 to 1998. He has been with the Department of Electrical and Computer Engineering,
National University of Singapore since June 1998 and is now an Associate Professor. His general research interests are in
the areas of mixed-signal and RF integrated circuits, and integrated MEMS and sensing systems. He is a Senior Member of IEEE.
Xiaofeng Wang was born in Shangqiu, China, in 1980. He received B.Eng. degree from Northwestern Polytechnical University, Xi'an, China,
in 2000 and M. Eng. degree from National University of Singapore, Singapore, in 2003, both in electrical engineering. He is
currently working toward the Ph.D. degree at Tufts University, Medford, USA. His research is on high speed ADC design.
Wai Hoong Sun was born in Taiping, Malaysia in 1976. He received the B. App. Sc. (Honours) degree in electrical engineering from the University
of Toronto, Canada in 1999. After graduating, he joined Sharp Electronics Singapore as an R&D Engineer where he was involved
in FPGA and digital IC design of display related circuits. In 2001 and 2002, he did full time research in the National University
of Singapore on bandpass sigma-delta modulators. During that period, he was also a Graduate Tutor in electronics for second
year electrical and computer engineering students. He then joined Philips Electronics Singapore in 2002 as a Lead Engineer.
He did board-level designs for LCD and plasma televisions. He was also development project leader for a project that was successful
in bringing to the market a range of LCD and plasma televisions. Currently, he is a Hardware Architect where he is responsible
for the system-level electrical design of the television board. 相似文献
996.
The thermal diffusivity and effective infrared emissivity of water–methanol mixtureswere measured at atmospheric pressure and ambient temperature using a pyroelectric thermal-wave resonator cavity. The applied frequency-scan method allows keeping the cavity length fixed, which eliminates instrumental errors and substantially improves the precision and accuracy of the measurements. A theoretical model describing conduction and radiation heat transfer in the cavity was developed. The model predictions and the frequency-scan experimental data were compared, showing excellent agreement. The measurements were performed for methanol volume fractions of 0, 0.5, 1, 2, 5, 10, 20, 40, 75, and 100%. The fitted thermal diffusivity and effective emissivity vs. concentration results of the mixtures were compared to literature theoretical and experimental data. The maximum resolution of 0.5% by volume of methanol in water by means of the thermal-wave cavity method is the highest reported to date using thermophysical techniques. Semi-empirical expressions for the mixture thermal diffusivity and infrared emissivity as functions of methanol concentration have been introduced. The expression for infrared emissivity is consistent with the physical principle of detailed balance (Kirchhoff’s law). The expression for thermal diffusivity was found to describe the data satisfactorily over the entire methanol volume-fraction range. 相似文献
997.
The electrical conductivity of Nb doped langasite (La3Ga4.75Nb0.25SiO14) was examined as a function of temperature and oxygen partial pressure by complex impedance spectroscopy. A pO2-independent regime was found at high pO2 followed by a pO2− 1/6 dependent regime at low pO2. A defect model consistent with these results was derived in which the electron density n is fixed by the density of ionized Nb donors at high pO2 and by the generation of oxygen vacancies at low pO2. The temperature and oxygen partial pressure dependence of the electron density was obtained independently by thermoelectric
power measurements. The Nb donor ionization energy was determined to be 1.52 ± 0.06 eV, confirming Nb to be a deep donor in
langasite. By combining conductivity and thermoelectric power data, an expression for the electron mobility given by μe = 1.1× 10− 2exp(
) was obtained. After evaluating the temperature dependent conductivity data under reducing conditions, in light of the defect
model, a value for the reduction enthalpy (Er = 6.57 ± 0.24 eV) was derived. 相似文献
998.
机抖激光陀螺抖动随机噪声概率分布的x^2检验 总被引:1,自引:0,他引:1
运用x^2检验方法对机抖激光陀螺(RLG)抖动噪声幅度的概率芬布进行了假设检验,证明了本文所采用的随机噪声注入方法能够保证抖动幅度的随机变化服从高斯概率密度分布。 相似文献
999.
The paper discusses dissipative quartz converters for monitoring the water contents of gases, liquids, and solids as well as for research on new materials, in which use is made of a quartz resonator and dielectric sensor. 相似文献
1000.
石英谐振式力传感器是一种输出为频率信号的数字式传感器。测试系统包括测量电路、测量控制软件和数据分析软件三部分 ,提供了一个集数据采集、检测、分析、处理为一体的测试系统。从工程实际出发 ,论述了该类传感器测试系统的开发与研究 ,并编制了相应的软件。 相似文献