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爱立信T28无发射故障维修
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作者 曲光楷 《家庭电子》 2003年第2期32-32,共1页
爱立信T28型手机推出到现在已有几年时间,已进入了维修期,各种故障不断出现,其中无发射就是一种较为典型的故障。这种故障最容易出现在发射电路的后级。该机发射电路后级电路图如附图所示。
关键词 爱立信 T28 无发射 故障维修 手机
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发射电流波形对瞬变电磁响应的影响 被引量:38
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作者 陈曙东 林君 张爽 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2012年第2期709-716,共8页
本文研究了不同发射电流波形对瞬变电磁(TEM)响应的影响,利用自由空间中回线作为目标体,推导出方波、梯形波、半正弦波、三角波激励的响应.研究表明:对于低电导率目标体,同种波形激励的响应在有发射电流期间(on-time)与无发射电流期间(o... 本文研究了不同发射电流波形对瞬变电磁(TEM)响应的影响,利用自由空间中回线作为目标体,推导出方波、梯形波、半正弦波、三角波激励的响应.研究表明:对于低电导率目标体,同种波形激励的响应在有发射电流期间(on-time)与无发射电流期间(off-time)的幅度相近,四种波形中方波激励响应最强.由于off-time采集可以获得更高的信噪比,因而探测低电导率目标体时一般采用方波激励,采集off-time信号.对于高电导率目标体,off-time响应幅度随电导率增加而迅速下降,而半正弦与三角波激励的on-time响应幅度基本不随电导率变化,因而航空TEM可以采用半正弦与三角波进行on-time采集,并通过适当地提高激励电流的基频,以提高信噪比与空间分辨率. 展开更多
关键词 瞬变电磁 发射电流波形 发射电流期间 无发射电流期间 航空电磁
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没有扫频仪,如何检修手机无发射故障
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作者 刘建青 《无线电》 2001年第12期34-35,共2页
关键词 手机 无发射故障 检修 扫频仪
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A 2.4GHz CMOS Monolithic Transceiver Front-End for IEEE 802.11b Wireless LAN Applications
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作者 池保勇 石秉学 王志华 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2005年第9期1731-1739,共9页
A 2. 4GHz CMOS monolithic transceiver front-end for IEEE 802. llb wireless LAN applications is presented. The receiver and transmitter are both of superheterodyne structure for good system performance. The frontend co... A 2. 4GHz CMOS monolithic transceiver front-end for IEEE 802. llb wireless LAN applications is presented. The receiver and transmitter are both of superheterodyne structure for good system performance. The frontend consists of five blocks., low noise amplifier,down-converter, up-converter, pre-amplifier, and LO buffer. Their input/output impedance are all on-chip matched to 50 Ω except the down-converter which has open-drain outputs. The transceiver RF front-end has been implemented in a 0. 18μm CMOS process. When the LNA and the down-converter are directly connected, the measured noise figure is 5.2dB, the measured available power gain 12. 5dB, the input l dB compression point --18dBm,and the third-order input intercept point --7dBm. The receiver front-end draws 13.6mA currents from the 1.8V power supply. When the up-converter and pre-amplifier are directly connected, the measured noise figure is 12.4dB, the power gain is 23. 8dB, the output ldB compression point is 1.5dBm, and the third-order output intercept point is 16dBm. The transmitter consumes 27.6mA current from the 1.8V power supply. 展开更多
关键词 wireless transceiver RF CMOS LNA mixer PREAMPLIFIER
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An analog front-end circuit for ISO/IEC 15693-compatible RFID transponder IC 被引量:4
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作者 LIU Dong-sheng ZOU Xue-cheng +1 位作者 YANG Qiu-ping XIONG Ting-wen 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第10期1765-1771,共7页
The 13.56 MHz analog front-end circuit for ISO/IEC 15693-compatible radio frequency identification (RFID) trans- ponder IC presented in this paper converts RF power to DC and extracts clock and data from the interroga... The 13.56 MHz analog front-end circuit for ISO/IEC 15693-compatible radio frequency identification (RFID) trans- ponder IC presented in this paper converts RF power to DC and extracts clock and data from the interrogator by 10% or 100% ASK modulation. The transponder sends data back to the interrogator by load modulation technology. The electrostatic discharge (ESD) protection circuits function to limit RF voltage to a safe level. An inductive coupling simulation modelling for 13.56 MHz RFID system is presented, with simulation results showing that the transponder operates over a wide range of electromagnetic field strength from Hmin (150 mA/m) to Hmax (5 A/m). The transponder IC is implemented in SMIC 0.35-μm three-metal two-poly mixed signal CMOS technology with embedded EEPROM. 展开更多
关键词 Radio frequency identification (RFID) ISO/IEC 15693 Transponder IC Analog front-end
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A compact transmit/receive switch for 2.4 GHz reader-less active RFID tag transceiver 被引量:1
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作者 Mohammad Arif Sobhan Bhuiyan Mamun Bin Ibne Reaz +2 位作者 Jubayer Jalil Labonnah Farzana Rahman Tae Gyu Chang 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第2期546-551,共6页
Radio frequency identification(RFID) is a ubiquitous identification technology nowadays. An on-chip high-performance transmit/receive(T/R) switch is designed and simulated in 0.13-μm CMOS technology for reader-less R... Radio frequency identification(RFID) is a ubiquitous identification technology nowadays. An on-chip high-performance transmit/receive(T/R) switch is designed and simulated in 0.13-μm CMOS technology for reader-less RFID tag. The switch utilizes only the transistor width and length(W/L) optimization, proper gate bias resistor and resistive body floating technique and therefore,exhibits 1 d B insertion loss, 31.5 d B isolation and 29.2 d Bm 1-d B compression point(P1d B). Moreover, the switch dissipates only786.7 n W power for 1.8/0 V control voltages and is capable of switching in 794 fs. Above all, as there is no inductor or capacitor used in the circuit, the size of the switch is 0.00208 mm2 only. This switch will be appropriate for reader-less RFID tag transceiver front-end as well as other wireless transceivers operated at 2.4 GHz band. 展开更多
关键词 body floating CMOS radio frequency identification(RFID) transmit/receive(T/R) switch TRANSCEIVER
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Research on CMOS Mm-Wave Circuits and Systems for Wireless Communications 被引量:2
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作者 JIA Haikun CHI Baoyong +6 位作者 KUANG Lixue YU Xiaobao CHEN Lei ZHU Wei WEI Meng SONG Zheng WANG Zhihua 《China Communications》 SCIE CSCD 2015年第5期1-13,共13页
This paper lenges in the design of discusses some chal- millimeter-wave (mln- wave) circuits and systems for 5th generation (5G) wireless systems in CMOS process. The properties of some passive and active devices ... This paper lenges in the design of discusses some chal- millimeter-wave (mln- wave) circuits and systems for 5th generation (5G) wireless systems in CMOS process. The properties of some passive and active devices such as inductors, capacitors, transmission lines, translbrmers and transistors in mm-wave frequency band are discussed. Self-healing technique dealing with PVT variation, res- onant mode switching technique to enhance frequency tuning range of voltage controlled oscillator (VCO) and dual mode technique for power amplifier (PA) efficiency enhancement are introduced. At last, A fully-integrated 60 GHz 5 Gb/s QPSK transceiver with the transmit/receive (T/R) switch in 65nm CMOS process is introduced. The measured error vector magnitude (EVM) of the TX is -21.9 dB while the bit error rate (BER) of the RX with a -52 dBm sine-wave input is below 8e-7 when transmitting/receiving 5 Gb/s data. The transceiver is powered by 1.0 V and 1.2 V supply (except the phase-frequency detector and charge-pump in the frequency synthesizer which are powered by 2.5 V supply) and con- sumes 135 mW in TX mode and 176 mW in RX mode. 展开更多
关键词 CMOS MM-WAVE devices VCO PA sell-healing TRANSCEIVER
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Clock generator and OOK modulator for RFID application
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作者 张利 王振华 +3 位作者 李永明 张春 王志华 陈弘毅 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2005年第10期1051-1054,共4页
The clock generator and OOK modulator for RFID (Radio Frequency Identification) presented in this paper consist of a current source and delay elements. The simple constant-gm structure is adopted in the current source... The clock generator and OOK modulator for RFID (Radio Frequency Identification) presented in this paper consist of a current source and delay elements. The simple constant-gm structure is adopted in the current source design and the current consumption of the current source is only about 2 μA. The delay elements, the clock generator and OOK modulator are introduced in detail in the paper. The designed circuits are fabricated by 0.6 μm CMOS process. The area of the core circuit is only about 400 μm×80 μm. The delay time of all three samples is in the range of 9 μs to 21 μs when the supply voltage varies from 2 V to 4 V. As the measured results satisfy the system requirements, these circuit structures are suitable for RFID application. 展开更多
关键词 RFID OOK CMOS Current source Delay elements
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A novel portable transmitter with 8 dBm output power for wireless communication equipments
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作者 张艳征 Mao Luhong +3 位作者 Zhou Xiaoqiu Zhang Shilin Deng Jianbao Xie Sheng 《High Technology Letters》 EI CAS 2014年第1期103-109,共7页
In this paper,a portable 2.42 GHz transmitter for wireless communication systems,with 8dBm output power and small size is proposed.Several novel features exist in this transmitter.First,power consumption and output ar... In this paper,a portable 2.42 GHz transmitter for wireless communication systems,with 8dBm output power and small size is proposed.Several novel features exist in this transmitter.First,power consumption and output are balanced by introducing a differential oscillator with input signal controlled biasing,which acts as both a carrier generator and an OOK modulator.Then,power consumption of the transmitter is reduced by the OOK modulated signal via switching the oscillator and the power amplifier at the same time.Furthermore,the area size is also reduced by a class-AB power amplifier,which uses the PCB antenna as the resonance inductance.With these features,the total chip area is reduced to 670μm×740μm(In a 0.18μm CMOS process). 展开更多
关键词 TRANSMITTER OOK modulator power amplifier CMOS 2.42GHz
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Compensation Method: New Perspectives
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作者 Boris Levin 《Journal of Physical Science and Application》 2014年第2期119-129,共11页
The compensation method aiming to reduce the irradiation on the user's body and to form a weak field area (a dark spot) in an antenna near region is considered. The results of the method development for the use in ... The compensation method aiming to reduce the irradiation on the user's body and to form a weak field area (a dark spot) in an antenna near region is considered. The results of the method development for the use in a narrow frequencies range are given. They show that under realistic conditions the compensation method allows reducing the irradiation power by a factor of 3-4 and more. The pattern changes are predictable and small, if the points of antennas placement are selected correctly. The dark spot necessity near the transmitter is not limited by mobile communication. A man often uses a low-power radio station, which is placed nearby in a vehicle, and it is necessary to protect from irradiation not only user but also other passengers. In the paper, it is shown that broadband field compensation can be achieved in various structures where the needed anti-phase fields are created either by identical antennas or by radiators located at equal distance from the compensation point, or by flat reflectors. 展开更多
关键词 Antenna theory COMPENSATION mobile antennas mutual coupling near fields
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Research on Logistics Sorting System based on RFID
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作者 Xingyu Xu YiBing Ma Yanfei Qin 《International Journal of Technology Management》 2013年第2期127-128,共2页
With the rapid development of express logistics business side, the traditional sorting has been unable to meet the needs of the logistics courier logistics development. In this case, the article combined with RFID rad... With the rapid development of express logistics business side, the traditional sorting has been unable to meet the needs of the logistics courier logistics development. In this case, the article combined with RFID radio frequency technology, put forward new ideas on the transformation of traditional logistics sorted. By adding RFID tags and binding RFID tags on waybill number, Comparison test validate and affirm that the RFID technology of sorting system is usability and ease of use. 展开更多
关键词 logistics management RFID the sorting system
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Interference-Free Determination of REEs in Electronic Waste Using ICP Optical Emission Spectroscopy
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作者 Jan Knoop Uwe Oppermann Jürgen Schram 《Journal of Chemistry and Chemical Engineering》 2014年第6期635-640,共6页
Recently, the demand for REEs (rare earth elements) has been heavily increasing, as they are used in many high-tech products (e.g., because of their specific magnetic behavior). As a result, the supply situation f... Recently, the demand for REEs (rare earth elements) has been heavily increasing, as they are used in many high-tech products (e.g., because of their specific magnetic behavior). As a result, the supply situation for REEs is worsening and the world market is depending on Chinese exports, so that it may be worthwhile to recycle e-waste (electronic waste) in European countries. This article describes an analytical method to analyze REEs in different kinds of e-waste with the help of a simultaneous ICP-OES (ICP optical emission spectrometer). The task is challenging because samples show significant differences in terms of major, minor and trace element concentrations. Depending on the field of application, the level of matrix elements and target elements differs completely, resulting in a wide variety of spectral interferences. The method presented in this article allows an accurate quantification of REEs as well as a high sample throughput. In addition to REEs, other elements of economic interest can be determined in the same way. The development of a sample preparation process is another important issue and considered as well. 展开更多
关键词 ICP-OES REE electronic waste E-WASTE GRINDING particle size analyzer microwave digestion spectral interferences.
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Terahertz emission from localized modes in one-dimensional disordered systems [Invited] 被引量:1
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作者 YONGQUAN ZENG GUOZHEN LIANG +11 位作者 Bo QIANG Bo MENG Hou KUN LIANG SHAMPY MANSHA JIANPING LI ZHAOHUI L LIANHE LI ALEXANDER GILES DAVIES EDMUND HAROLD LINFIELD YING ZHANG YIDONG CHONG AND Qi JIE WANG 《Photonics Research》 SCIE EI 2018年第2期117-122,共6页
We demonstrate terahertz(THz) frequency laser emission around 3.2 THz from localized modes in one-dimensional disordered grating systems. The disordered structures are patterned on top of the double-metal waveguide of... We demonstrate terahertz(THz) frequency laser emission around 3.2 THz from localized modes in one-dimensional disordered grating systems. The disordered structures are patterned on top of the double-metal waveguide of a THz quantum cascade laser. Multiple emission peaks are observed within a frequency range corresponding to the bandgap of a periodic counterpart with no disorder, indicating the presence of mode localization aided by Bragg scattering. Simulations and experimental measurements provide strong evidence for the spatial localization of the THz laser modes. 展开更多
关键词 (290.4210) Multiple scattering (040.2235) Far infrared or terahertz (140.5965) Semiconductor lasers quantumcascade.
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Watermark in the Digital Video Broadcasting Handheld Transmission Signal
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作者 胡玲娜 蒋铃鸽 +1 位作者 何晨 杨峰 《Journal of Shanghai Jiaotong university(Science)》 EI 2009年第2期149-153,共5页
Transmitter identification(TxID) technique is used to diagnose the operation status of radio transmitters in DTV distributed transmission network.A new TxID method for digital video broadcasting-handheld (DVB-H) syste... Transmitter identification(TxID) technique is used to diagnose the operation status of radio transmitters in DTV distributed transmission network.A new TxID method for digital video broadcasting-handheld (DVB-H) system is proposed.Watermark is embedded in the DVB-H signal to form the composite signal.According to watermarking theory we demonstrate the required signal level for watermarking signal to achieve given bit error probability under different circumstance.By selecting the reference pattern to generate watermarking signal,peak-to-average power ratio(PAPR) of the transmitted signal can be improved.Simulation results show that even in wireless situation the receiver can distinguish the watermarking signal with low embedding strength, and distortion to the host signal can also be ignored. 展开更多
关键词 transmitter identification (TxID) WATERMARK peak-to-average power ratio (PAPR)
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