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A dual-mode analog baseband with digital-assisted DC-offset calibration for WCDMA/GSM receivers

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Journal of Semiconductors 2011年第12期32卷 95-100页

作者：谢任重江晨李伟男黄煜梅洪志良 State Key Laboratory of ASIC and System Fudan University

A dual-mode analog baseband with digital-assisted DC-offset calibration （DCOC） for WCDMA/GSM receiver is presented. A digital-assisted DCOC is proposed to solve the DC-offset problem by removing the DC- offset component only. This method has no bandwidth sacrifice. After calibration the measured output residual offset voltage is within 5 mV at most gain settings and the IIP2 is more than 60 dBm. The baseband is designed to be reconfigurable at bandwidths of 200 kHz and 2.1 MHz. Total baseband gain can be programmed from 6 to 54 dB. The chip is manufactured with 0.13μm CMOS technology and consumes 10 mA from a 1.5 V supply in the GSM mode including an on-chip buffer while the core area occupies 1.2 mm^2.

关键词： analog baseband digital-assisted DCOC reconfigurable receiver

Multitone-based Non-linear Phase Variation Estimation for Analog Front-Ends in GNSS receivers

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Multitone-based Non-linear Phase Variation Estimation for An...

Acquisition of Weak Signals in Multi-Constellation Frequency Domain receivers

第五届中国卫星导航学术年会

作者： Chen Feiqiang Nie Junwei Li Zhengrong Wang Feixue School of Electronic Science and Engineering National University of Defense Technology

ISBN: (纸本)9783642547362

For high precision GNSS applications, accurate online measurements and calibrations of non-linear phase variation of analog front-ends at receivers is indispensable. Previous approaches are designed for off-line measurements, which rely on expensive instruments such as vector network analyzer (VNA). Therefore, they cannot facilitate online measurements, where the frequency response of analog front-end varies over time. Against this background, a novel multitone-based estimation method is proposed. Specifically, a multitone signal is injected into the front-end, while maximum likelihood (ML) estimation and least square (LS) linear fitting are performed at the output signals in order to estimate the non-linear phase variation. The proposed method could be conveniently realized at the GNSS receivers for online measurements. The accuracy of the proposed method is validated through comparisons with a benchmark Agilent VNA.

关键词： Non‐linear phase variation GNSS receiver multitone signal estimation.

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Positioning 2013年第2期4卷 144-152页

作者： Kaveh Mollaiyan Rock Santerre René Jr. Landry Department of Electrical Engineering école de Technologie Supérieure Montreal Canada Department of Geomatics Sciences Université Laval Quebec Canada Department of Electrical Engineering école de Technologie Supérieure Montreal Canada

New positioning applications’ availability requirements demand receivers with higher sensitivities and ability to process multiple GNSS signals. Possible applications include acquiring one signal per GNSS constellation in the same frequency band and combining them for increased sensitivity or predicting acquisition of other signals. Frequency domain processing can be used for this purpose, since it benefits from parallel processing capabilities of Fast Fourier Transform (FFT), which can be efficiently implemented in software receivers. On the other hand, long coherent integration times are mainly limited due to large FFT size in receivers using frequency domain techniques. A new method is proposed to address the problems in frequency domain receivers without compromising the resources and execution time. A pre-correlation accumulation (PCA) is proposed to partition the received samples into one-code-period blocks, and to sum them together. As a result, the noise is averaged out and the correlation results will gain more power, provided that the relative phase between the data segments is compensated for. In addition to simplicity, the proposed PCA method enables the use of one-size FFT for all integration times. A post-correlation peak combination is also proposed to remove the need for double buffering. The proposed methods are implemented in a configurable Simulink model, developed for acquiring recorded GNSS signals. For weak signal scenarios, a Spirent GPS simulator is used as a source. Acquisition results for GPS L1 C/A and GLONASS L1OF are shown and the performance of the proposed technique is discussed. The proposed techniques target GNSS receivers using frequency domain processing aiming at accommodating all the GNSS signals, while minimizing resource usage. They also apply to weak signal acquisition in frequency domain to answer the availability demand of today’s GNSS positioning applications.

关键词： FFT Acquisition Frequency Domain receiver Weak Signal Multi-Constellation

Limited Bandwidths and Correlation Ambiguities: Do They Co-Exist in Galileo receivers

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Positioning 2011年第1期2卷 14-21页

作者： Elena Simona Lohan 不详

Galileo is the Global Navigation Satellite System that Europe is building and it is planned to be operational in the next 3-5 years. Several Galileo signals use split-spectrum modulations, such as Composite Binary Offset Carrier (CBOC) modulation, which create correlation ambiguities when processed with large or infinite front-end bandwidths (i.e., in wideband receivers). The correlation ambiguities refer to the notches in the correlation shape (i.e., in the envelope of the correlation between incoming signal and reference modulated code) which happen within +/– 1 chip from the main peak. These correlation ambiguities affect adversely the detection probabilities in the code acquisition process and are usually dealt with by using some form of unambiguous processing (e.g., BPSK-like techniques, sideband processing, etc.). In some applications, such as mass-market applications, a narrowband Galileo receiver (i.e., with considerable front-end bandwidth limitation) is likely to be employed. The question addressed in this paper, which has not been answered before, is whether or not this bandwidth limitation can cope inherently with the ambiguities of the correlation function, to which extent, and which the best design options are in the acquisition process (e.g., in terms of time-bin step and ambiguity mitigation mechanisms).

关键词： Binary Offset Carrier (BOC) Composite Binary Offset Carrier (CBOC) Galileo Global Navigation Satel-lite Systems (GNSS) Narrowband GNSS receiver Unambiguous Acquisition

Particles in a circulation loop for solar energy capture and storage

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Particuology 2019年第2期17卷 149-156页

作者： Q. Kang G. Flamant R. Dewil J. Baeyens H.L. Zhang Y.M. Deng KU Leuven Department of Chemical Engineering Process and Environmental Technology Lab. 2860 Sint-Katelijne-Waver Belgium Processes. Materials and Solar Energy Laboratory PROMES-CNRS 66120 Font Romeu France European Powder & Process Technology 3120 Tremelo Belgium Beijing University of Chemical Technology School of Life Science and Technology Beijing 10029 China

This study defines and assesses the selection ciiteria for suitable particulate materials to be used in an upflow bubbling fluidized bed (UBFB) or dense up-flow powder circulation system for solar energy capture and storage. The main criteria identified are based on the thermophysical and thermomechanical properties, attrition behavior, and the considerations of health and environmental hazards of the candidate powders. Finally, a cost comparison and tentative ranking of the different can didate powders is presented in addition to a weighted scoring. Significant scoring differences can be observed between the various materials. Olivine possesses the most favorable characteristics and appears to be the particulate material of choice for solid/gas suspension heat transfer fluids.

关键词： Concentrated solar power Particle-in-tube receiver Particle properties Selection criteria

Geodynamic processes of the continental deep subduction: Constraints from the fine crustal structure beneath the Pamir plateau

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Science China Earth Sciences 2020年第5期63卷 649-661页

作者： Wei LI Yun CHEN Ping TAN Xiaohui YUAN State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China Institute of Disaster Prevention Sanhe 065201China Deutsches GeoForschungsZentrum GFZ Telegrafenberg14473 PotsdamGermany

The Pamir plateau,located north of the western syntaxis of the India-Eurasia collision system,is regarded as one of the most possible places of the ongoing continental deep *** on a N-S trending linear seismic array across the Pamir plateau,we use the methods of the harmonic analysis of receiver functions and the cubic spline interpolation of surface wave dispersions to coordinate their resolutions,and perform a joint inversion of these datasets to construct a 2-D S-wave velocity model of the crust and uppermost mantle there.A spatial configuration among the intermediate-depth seismicity,Moho topography,and low-velocity anomalies within the crust and upper mantle is revealed,which provides new seismological constraints on the geodynamic processes of the continental *** results not only further confirm the deep subduction of the Asian continental lower crust beneath the Pamir plateau,but also indicate the importance of the metamorphic dehydration of the subducting continental crustal material in the genesis of the intermediate-depth seismicity and the crustal deformation.

关键词： Pamir plateau Continental deep subduction Intermediate-depth seismicity Low-velocity zone receiver function Ambient noise Joint inversion

A monolithic 3.1-4.8 GHz MB-OFDM UWB transceiver in 0.18-μm CMOS

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Journal of Semiconductors 2010年第6期31卷 109-117页

作者：郑仁亮江旭东姚望杨光尹江伟郑剑钦任俊彦李巍李宁 State Key Laboratory of ASIC and System Fudan University Micro-/Nano-Electronics Science and Technology Innovation Platform Fudan University

A monolithic RF transceiver for an MB-OFDM UWB system in 3.1-4.8 GHz is *** transceiver adopts direct-conversion architecture and integrates all building blocks including a gain controllable wideband LNA,a I/Q merged quadrature mixer,a fifth-order Gm-C bi-quad Chebyshev LPF/VGA,a fast-settling frequency synthesizer with a poly-phase filter,a linear broadband up-conversion quadrature modulator,an active D2S converter and a variablegain power *** ESD protected transceiver is fabricated in Jazz Semiconductor＇s 0.18-μm RF CMOS with an area of 6.1 mm^2 and draws a total current of 221 mAfrom 1.8-V *** receiver achieves a maximum voltage gain of 68 dB with a control range of 42 dB in 6 dB/step,noise figures of 5.5-8.8 dB for three sub-bands,and an inband /out-band IIP_3 better than-4 dBm/＋9 *** transmitter achieves an output power ranging from-10.7 to-3 dBm with gain control,an output P_（1dB） better than-7.7 dBm,a sideband rejection about 32.4 dBc,and LO suppression of 31.1 *** hopping time among sub-bands is less than 2.05 ns.

关键词： MB-OFDM UWB transceiver receiver transmitter synthesizer

Mantle transition zone structure beneath the Central Asian Orogenic Belt

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Science China Earth Sciences 2020年第4期63卷 548-560页

作者： Jing HE Qingju WU Key Laboratory of Crustal Dynamics Institute of Crustal DynamicsChina Earthquake AdministrationBeijing 100085China Key Laboratory of Seismic Observation and Geophysical Imaging Institute of GeophysicsChina Earthquake AdministrationBeijing 100081China

Over the past decades, there have been hot debates in the geodynamic community regarding to the deep evolution mechanisms of Cenozoic volcanism in the Central Asian Orogenic Belt(CAOB). Of all the constraints available, high resolution structure of upper mantle discontinuities, especially the discontinuities at depths of 410 km(D410) and 660 km(D660), is of the most important, which may provide reliable clues on the magma channel as well as its evolution. In this work, we adopt the common conversion point stacking technique with teleseismic radial P-wave receiver functions to examine the D410 and D660 discontinuities. The primary results exhibit that the major characteristics of the mantle transition zone(MTZ) obtained by different velocity models are largely consistent. Obviously elevated D410 and slightly depressed D660 are observed beneath the Hannuoba Volcano, suggesting possible delamination of the local lithosphere deposited at the D410. This process may induce upwelling of the asthenospheric materials filling the space left by the delaminated lithosphere, and subsequently trigger volcanic eruptions. Strong depressions are observed at both D410 and D660 depths beneath west of the Dariganga Volcano, and the depression of D660 is more pronounced. It leads to the apparently thickened MTZ, indicating the presence of cold material at the D660. This cold material is speculated as a stagnant slab from the subducted Pacific Plate or the remains of a detached island arc system from the collision and formation of the CAOB. Slightly thinner MTZ is found beneath the Hentey Mountains and the Middle Gobi Volcano. Apparently, this thinner MTZ is not significant enough to support the existence of high thermal anomalies,which may rule out the possibility of large-scale hot material upwelling from either the local MTZ or even the lower mantle.

关键词： Central Asian Orogenic Belt Cenozoic Volcano Mantle transition zone receiver function

A 2-step GPS carrier tracking loop for urban vehicle applications

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Journal of Systems Engineering and Electronics 2017年第5期28卷 817-826页

作者： Hongyang Zhang Luping Xu Yue Jian Xiaochen Ma School of Aerospace Science and Technology Xidian University Xi'an Flight Automatic Control Research Institute Aviation Industry Corporation of China Xi'an Aeronautics Computing Technique Research Institute Aviation Industry Corporation of China

Global positioning system (GPS) for vehicle applications in the urban area is challenged by low signal intensity. The carrier loop based on fast Fourier transform (FFT) can obtain a high signal to noise ratio (SNR) gain by increasing the observation time. However, this leads to a major problem that the acceleration cannot be ignored. The performance of the FFT-based loop will decline with the acceleration increasing. This paper discusses the effect of the dynamic on FFT first. Then a high performance carrier tracking loop for weak GPS L5 signals is proposed. It combines discrete chirp-Fourier transform (DCFT) and the phase fitting method to estimate Doppler frequency and Doppler rate simultaneously. First, a sequence of integration results is used to perform DCFT to estimate coarse Doppler frequency and Doppler rate. Second, the phase of the sequence is calculated and used to perform linear fitting. By the phase fitting method, the fine Doppler frequency and Doppler rate can be estimated. The computation cost is small because the integration results are used and the phase fitting method needs only coarse estimates of Doppler frequency and Doppler rate. Compared with FFT and DCFT, the precision of the phase fitting method is not limited by the resolution. Thus the proposed loop can get high precision and low carrier to noise ratio (C/N-0) tracking threshold. Simulation results show this loop has a great improvement than conventional loops for urban weak-signal applications.

关键词： satellite navigation receiver signal processing frequency lock loop