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1.
New relay equipment for a tunnel relay system used in an 800 MHz band land mobile telephone network has been developed. Significant improvements in size and power consumption have been achieved using a predistortion (PD) circuit to compensate for third-order intermodulation (IM) distortion generated in the power amplifier. This predistortion circuit features a simple configuration and easy adjustment, as well as high distortion reduction performance. The circuit configuration is derived from an analysis based on a complex power series representation of input-output nonlinearities for microwave transistor amplifiers. This analysis shows that two kinds of nonlinearities, AM-AM and AM-PM conversions, are uniquely related through the third-order distortion phase, In addition, an automatically controlled predistortion system is introduced to establish an adjustment and maintenance-free compensator. Using the developed predistortion circuit, a stable distortion reduction of more than 20 dB per 25 MHz bandwidth has been attained.  相似文献   

2.
Conn  D.R. Maciejko  R. 《Electronics letters》1979,15(17):516-517
The results of a user-density analysis for different systems using the 800 MHz frequency band for mobile radiotelephone communications are presented. Our theoretical investigations show that digital phase-shift keying (p.s.k.), double-binary modulation and analogue s.s.b. systems outperform analogue f.m. systems by a factor of approximately two when compared on a user-density basis.  相似文献   

3.
Hikita  M. Akagi  T. 《Electronics letters》1992,28(22):2037-2038
A new-type single balanced mixer which satisfies the specifications of E-TACS (extended total access communication system) ultra-wideband cellular radio has been developed. The circuit is constructed with a single ferrite hybrid coil, two GaAs FETs and an IF coil, which provide good spurious-response characteristics for arbitrary intermediate frequencies. Miniaturisation of the front-end module is achieved by using SAW filters and the above mixer.<>  相似文献   

4.
5.
介绍了在36°YXLiTaO_3基片上采用镜像阻抗连接换能器结构研究制作出900MHz高频低损耗声表面波滤波器,插入损耗小于5dB、带外抑制优于50dB。  相似文献   

6.
A method is presented to derive a propagation model to predict the received median signal voltage for an 800-MHz mobile radio system. Results are given of an investigation into the performance of a particular model that was derived using this method. The method uses a Kalman filter that uses propagation measurements to derive a best fit for a particular propagation model to the measured data. The model that was derived is based on propagation measurements made in the State of Florida. The new propagation model uses a plane-Earth propagation model that is corrected with an environmental propagation loss term that takes into account the various environmental effects near the mobile unit. The parameters in the environmental propagation loss model were determined using a Kalman filter that computes minimum mean square estimates of the parameters using measured propagation data. The environmental propagation loss term accounts for the effects of Earth diffraction, hills, valleys, urban and suburban areas, bare and grass-covered ground, bushes, trees, swamps, and propagation over fresh and salt water. It was found that, with the 800-MHz propagation model derived with this method, the prediction error for the received median signal voltage had a standard deviation of 5.08 dB  相似文献   

7.
The design and installation of a mobile radio system involves the evaluation or prediction of the propagation characteristics associated with the geographical area of interest. A wide variety of prediction techniques has been developed for different mobile environments, so that the task of selecting an appropriate propagation prediction method can be difficult and complex. This is especially true for systems operating in the upper-UHF band of 800-950 MHz, where mobile radio services are rapidly growing. A practical comparison is given of current prediction techniques available in the literature (for slow lognormal fading rather than multipath Rayleigh fading), with an emphasis on three essential criteria to consider in the selection process: the type of terrain or geography covered by each method, the form of prediction provided (e.g., transmission loss estimates, field strength contour maps, etc.), and the implementation difficulty and degree of sophistication.  相似文献   

8.
800-MHz frequency synthesizers, constructed by the 800- MHz directly divided method, are presented. High spectral purity and fast channel switching time are obtained. These synthesizers contribute to the simplification of the local oscillator vehicular equipment.  相似文献   

9.
设备检测的目的和作用是从源头上减少和避免干扰,随着无线电通信技术的发展,电磁环境日趋复杂,无线电干扰也日趋复杂,在这样的形势下,检测工作的重要性不言而喻。要做好检测工作需从四个环节人手,即测试仪表、被测设备、测试标准和测试方法。我们对测试仪表、测试标准和测试方法的分析探讨比较多,然而对被测设备的分析研究,对我们的检测工作同样重要,知己知彼才能百战百胜。  相似文献   

10.
905MHz低相噪声表面波振荡器的设计   总被引:2,自引:0,他引:2       下载免费PDF全文
本文分析了声表面波谐振器的性能 ,论述了声表面波振荡器的工作原理及设计方法 ,最终完成中心频率为 90 5MHz的振荡电路 ,相位噪声低于 - 110dBc/Hz/ 1kHz。文中对影响相位噪声的因素进行了分析讨论  相似文献   

11.
Compact bandpass filters for 800-MHz land mobile radio equipment has been developed using coaxial resonators with a high dielectric constant material of εr= 35. The use of dielectric material of high Q and a dielectric substrate for coupling capacitors made possible the construction of compact low-insertion-loss filters. The performance characteristics of these filters are described.  相似文献   

12.
A compact voltage-controlled oscillator, covering 1000 channels with a single range, has been designed and fabricated using GaAs varactor diodes. A c.n.r. of more than 76 dB with 25 kHz offset from carrier and an s.n.r.of more than 52 dB are obtained. Their performance characteristics are described.  相似文献   

13.
14.
The 800-MHz band land mobile telephone system which is going into service in Tokyo and other major cities is described. This system is characterized by 1) an ordered array of cells which allows each radio channel to be reused by spacing at an appropriate coordination distance in a wide service area (cellular system), 2) development of a new higher frequency band, and 3) a fully automatic exchange system integrated with the ordinary telephone network. Field tests have been carried out in the Tokyo metropolitan area since 1975 and have now been brought to a successful completion.  相似文献   

15.
An Amplitude Shift Keying (ASK) transceiver for RFID applications is presented in this paper. The proposed transceiver is suitable for communications with electronic devices that are powered through an inductive link. The circuit has been designed to be compatible with the communication standards ISO 14443. It operates at 13.56 MHz with a communication speed from 200 kHz up to 847 kHz. In modulation mode of operation, a solution based on programmable CMOS inverters is proposed to control the modulation depth in the range [0–100%]. The demodulator has been designed using versatile current rectifier and a simple operational transconductance amplifier stage. The proposed transceiver was implemented in a standard 0.5 μm CMOS process. The circuit covers an area of 2 mm2 and the total DC power consumption is lower than 5.3 mW under 4V DC supply voltage. Stéphane Meillére has received the Engineer degree in Microelectronics from the ISEN-Toulon, Institut Supérieur d’Electronique et du Numérique, School at Toulon in 2000 and the M.Sc. and Ph.D. degrees from the University of Provence Aix-Marseille I, France, in 2000 and 2004, respectively, all in Microelectonics. From 2003 to 2005, he worked as a Research Engineer at the ISEN-Toulon. Since 2005 he joined the University of Provence as an Assistant Professor. His research interests are mainly in the design of full custom ASICs. He integrated in the same time the Integrated Circuits Design Team at the L2MP laboratory. He worked on different research project with industry. Hervé Barthélemy has received the MSc degree in Electrical Engineering in 1992 and the PhD degree in Electronics from the University of Paris XI Orsay, France in 1996. In 2002 he received the HDR degree from the University of Provence, Aix-Marseille I, France. From 1996 to 2000 he was an Assistant Professor at the Institut Supérieur d’Electronique de la Méditerranée (ISEN) in Toulon, France. Since 2000 he joined the University of Provence where is has been a full Professor in 2005. Since 2005 he has headed the Integrated Circuits Design Team at the L2MP laboratory. The team counts 12 Researchers and 20 PhD students and is involved in several research projects with industry. His research interests are mainly in the design of radiofrequency analog integrated circuits. He authored and co-authored multiple publications in international journals and conference proceeding. Michel Martin received an engineering degree in applied physics, option Micro-electronics from Ecole Nationale Supérieure de Physics in Marseille in 1991. He worked previously in ST Microelectronics, and he was involved in the design of the Smart Card Group’s product. He joined Gemplus in ’91 where he designed chips for secured smart cards memories. In 1995, he was the Co-founder of INSIDE Contactless. He was involved in the analog and EEPROM memories designs for contact and contactless chips. Michel was promoted I.C. Design Director with a team of 15 people divided on 2 Design Centers. He still maintains an active part in the chip Design. He is also the responsible for technical interface with the foundries to develop EEPROM memory bit cell, and improve the new processes dedicated the smart cards application.  相似文献   

16.
《Microelectronics Journal》2007,38(10-11):1070-1081
A low power high data rate wireless endoscopy transceiver is presented. Transceiver architecture, circuit topologies and design trade-offs have been considered carefully to satisfy the tight requirements of the medical endoscopy capsule: lower power consumption, high integration degree and high data rate. The prototype, implemented in 0.25 μm CMOS, integrates a super-heterodyne receiver and a super-heterodyne transmitter on a single chip together with an integrated RF local oscillator and LO buffers. The digital modulation and demodulation is also implemented in analog field and no data converters are needed for the whole endoscopy capsule. The measured sensitivity of the receiver is about −70 dBm with a data rate 256 kbps, and the measured output power of the transmitter could achieve −23 dBm with a data rate 1 Mbps. The transceiver operates from a power supply of 2.5 V, while only consuming 15 mW in receiver (RX) mode and 14 mW in transmitter (TX) mode.  相似文献   

17.
18.
Microwave SAW bandpass filters for spacecraft applications   总被引:1,自引:0,他引:1  
Microwave SAW bandpass filters for spacecraft applications are described. Two SAW bandpass filters were designed and fabricated in the 1.5 GHz band using temperature-stable ST-cut quartz substrates. The SAW bandpass filters were then assembled in a SAW filter bank. One unique feature of the SAW filter bank is that a broader band is available merely by adding the outputs of SAW bandpass filters adjacent in the frequency domain. Measured electrical responses as well as results of a transmission experiment show satisfactory performance. Effects of the temperature and aging stability characteristics are investigated based on the measured and calculated responses  相似文献   

19.
In this paper, a single-input single-output-/multipleinput multiple-output- (SISO-/MIMO-) OFDMA uplink baseband transceiver based on IEEE 802.16e-2005 is proposed. To compensate for the interference of carrier frequency offset (CFO), an inter-carrier interference-based (ICI-cancellationbased) CFO estimator in conjunction with channel estimation and MIMO detector is proposed. Moreover, a low complexity solution for implementation is also provided. Simulation results show that the mean-square-error (MSE) performance of the proposed CFO estimator can be reduced to about one tenth compared to other methods and the bit-error-rate (BER) performance of the proposed transceiver is quite close to that of an ideal system that doesn?t include CFO compensation.  相似文献   

20.
This paper describes the design and performance of the first tri-band (2100, 1900, 800/850 MHz) single-chip 3G cellular transceiver IC for worldwide use. The transceiver has been designed to meet all narrowband blocker, newly proposed Adjacent Channel II, and Category 10 HSDPA (High Speed Downlink Packet Access) requirements. The design is part of a reconfigurable reference platform for multi-band, multi-mode (GSM/EDGE + WCDMA) radios. The zero-IF receiver is comprised of a novel multi-band quadrature mixer, seventh-order baseband filtering, and a novel DC offset correction scheme, which exhibits no settling time or peak switching transients after gain steps. The receiver lineup is designed to optimize HSDPA throughput and minimize sensitivity to analog baseband filter bandwidth variations. The direct-launch transmitter is made up of a third-order baseband filter, an I/Q modulator with variable gain, an integrated transformer, an RF variable gain amplifier, and a power amplifier driver. At +9.5-dBm output power, the transmitter achieves an error vector magnitude (EVM) of 4%. Fractional-N synthesizers achieve fast lock times of 50 /spl mu/s (150 /spl mu/s) within 20 ppm (0.1 ppm). Automatically calibrated, integrated VCOs achieve a 1.6-GHz tuning range to facilitate coverage over all six 3GPP frequency bands. The IC draws 34 mA in receive (18-mA receiver plus 16-mA fractional-N PLL/VCO) and 50 to 62 mA in transmit (-76 dBm to +9.5 dBm), including PLL/VCO, using a 2.775-V supply voltage. The RF transceiver is integrated with the baseband signal processing and associated passives in a 165-pad package, resulting in the first tri-band 3G radio transceiver with a digital interface which requires no external components.  相似文献   

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