伪超外差连续波收发器一种新型无线收发器的设计

本文介绍一种近年开发的实验新型收发器，它是作为莫尔斯电码(开-关键控)工作用的，使用了非同寻常的架构。因为此架构开发者在其他地方从未见过，所以是新的，其特点是把直接变频和超外差巧妙地结合起来，得到一种新的设计方法。其性能完全能满足无线电爱好者设备的要求。     

LMX3162单片集成无线收发器

ＬＭＸ３１６２是Ｎａｔｉｏｎａｌ半导体公司推出的单片集成无线收发器,该芯片在一块器件上集成了无线接收和发送两种功能,可用于ＩＳＭ２．４５ＧＨＺ无线系统、无线个人通信（ＰＣＳ／ＰＣＮ）系统６、无线 域网（ＷＬＡＮＳ）和其它无线通信系统中,本文介绍了ＬＭＸ３１６２的原理、特点和典型应用。     

ZigBee无线收发器基带单元的设计

随着通信技术的不断发展,短距离无线通信已成为无线通信技术的新热点。符合IEEE802.15.4标准的ZigBee技术具备低价格、低功耗等优点,因而ZigBee芯片在工业控制,智能家居等方面具有很强的市场前景。重点讨论了ZigBee无线收发器的基带单元设计方案,并用MATLAB进行了仿真。     

无线音频收发器

CC8520是一款采用2．4GHz片上系统的音频收发器,可通过RF链路在无噪声与压降的条件下,传输未压缩的CD音质级无线音频。与现有解决方案相比,无烦人的噪声（噼噗或咔嗒声）与高平均压降时间（MTBD）;具有与蓝矛（Bluetooth）、WLAN以及其他2．4GHz设备出色的共存性;     

MICRF005无线收发器的原理和应用

MICRF005芯片是Micrel公司生产的一种高速无线UHF收发器，是一款单芯片OOK收发器，可用于远距离低功率无线设备中单向和双向无线连接。MICRF005采用“天线输入，数据输出”工作方式，所有RF和IF调谐均可在集成电路内自动完成，因此具有很高的可靠性和极低的功耗。文中介绍了MICRF005的主要特点、结构原理和引脚功能，最后给出了它的应用电路。     

一种基于多无线收发器的无线自组网服务质量保障机制

为了提高无线自组网的容量,满足多媒体任务的服务质量(QoS)要求,该文引入多无线收发器技术,扩展单接口单信道下的无状态QoS模型SWAN为多接口多信道下的无状态QoS模型MMSWAN。同时,提出一种多接口多信道下的QoS路由协议MMQAODV,通过与MMSWAN的结合,实现了一种跨层的QoS保障机制。模拟试验表明,这种机制有效地提高了多媒体任务的QoS和尽力而为任务的性能,与SWAN相比延迟减少为它的2%~27%左右,提交的尽力而为数据量为它的1.29~3.55倍。     

SPIRITl：无线收发器

意法半导体推出一款高性能、超低功耗的无线收发器,目标应用包括自动读表系统和其他的内置无线传感器节点的设备,例如报警系统、安全系统、家庭与楼宇自动化和工业监控系统、SPIRITl收发器可处理住户或商户的智能电表与供电公司调控中心没置的数据集中器之间的通信。     

nRF~(TM)系列单片无线收发器的应用设计

nRF~(TM)系列ISM频段单片无线收发器集成了高频发射/接收、PLL合成、FSK/GMSK调制、多频点切换等功能,可广泛应用于无线数据传送系统及产品。还简单介绍了其应用特性及设计要点。     

用于RFID的平面倒F天线的FDTD设计分析

基于平面倒F天线模型,设计了一种小型的适合用于RFID系统射频标签的微带贴片天线,工作在0.915 GHz频率上.利用基于非均匀网格的时域有限差分方法(Non-uniform Fitine-difference Time-domain,nu-FDTD)对该天线的设计过程进行了建模和仿真,分析了辐射贴片结构的变化对天线的回波损耗的影响,进而对天线进行优化,使得这种平面倒F天线能够适应射频标签天线的需要.     

Analysis of Spatial Transfer Function by Using FDTD for Wireless Communication

Spatial transfer function for wide band wireless communication system is analyzed by using FDTD and DFT method. Ray-based method is not sufficiently accurate, when the size of objects on the propagating path is comparable to the wavelength. In our proposed method, the tranfser function can be obtained exactly by using the FDTD method. For the numerical examples, the transfer functions in an aperture of the waveguide are calculated by proposed procedure. Furthermore, experimental verification is made by using two-dimensional propagation system, which is constructed of copper plates, antennas and vector network analyzer. The proposed algorithm is valid for estimating of the spatial transfer function.     

Efficient EVM Testing of Wireless OFDM Transceivers Using Null Carriers

High-volume manufacturing of current generation orthogonal frequency division multiplexing (OFDM transceivers mandates testing for error-vector-magnitude (EVM) at production testing. During EVM test, a modulated RF input signal is down-converted and demodulated to obtain the output baseband digital data and EVM is computed by processing the baseband digital data. Hence, production testing of OFDM devices would require such modulation- and demodulation-capable automated test equipment (ATE) to perform EVM test. Such capabilities significantly add up to the cost of the ATE, thereby increasing the overall cost of testing. Moreover, test time for EVM can be relatively long compared to other tests due to the need to average over a large number of data bits. In this paper, we propose a methodology for testing EVM using multi-tone signals sourced from inexpensive signal sources that generate standard constellations. Moreover, introducing null carriers in the multi-tone test stimulus enables accurate characterization of system noise with reduced number of data bits. This enables significant speedup in EVM testing. We present the theory to corroborate the proposed approach along with simulation and hardware results. The proposed test method also has the potential to significantly reduce EVM test time under production test conditions.      

Reconfigurable Transceivers for Wireless Broadband Access Schemes

Though code division multiple access (CDMA) and orthogonal frequency division multiple access (OFDMA) are potential candidates for future broadband wireless access schemes, the requirements of the users may not be completely supported by a single communication system. Therefore, for easy connectivity and compatibility with the existing communication systems and to support various quality-of-service (QoS) requirements, systems with dynamic reconfigurability are inevitable. This article gives an overview of CDMA, OFDMA, and other block-based transmissions, and proposes a reconfigurable transceiver whose blocks can be configured in order to support any of the above air interfaces. The reconfigurable transceiver allows low-cost implementation of multiple air interfaces in a single terminal and achieves optimal QoS based on the available wireless networks.     

System-Level Specification Testing Of Wireless Transceivers

This paper presents an efficient system-level manufacturing test methodology for wireless transceiver systems. Conventional system-level testing procedures incur large test times and require the use of multiple test hardware configurations for measuring frequency and modulation-domain performance specifications, e.g., system-gain, nonlinearity, noise-figure, channel power, adjacent-channel power-ratio, error vector magnitude, modulation signal-to-noise ratio and bit error rate. The proposed test methodology addresses these problems by simplifying the test stimulus application and test response capture/analysis procedures. In addition, the number of test hardware configurations needed to measure all the performance specifications is minimized and fewer as well as shorter tests are used to determine all the test specification values of interest. Test accuracy is achieved by optimizing the test stimulus so that the observed response has strong statistical correlation with the target test specification values. Experimental results show significant testing time reduction and was validated on 1.575 GHz and 900 MHz wireless transceiver prototypes.     

倒装芯片封装的FDTD分析

采用FDTD方法对倒装芯片封装和过孔的不连续性进行分析,在对共面波导加激励源时采用了线激励的方式,降低了编程的难度。同时我们采用高频电磁场分析软件HFSS进行建模仿真,能够得到两种方法的结果比较吻合,验证了文中这种激励方法的可行性。最后分析了采用局部匹配法对倒装芯片不连续性能的改善,使用该方法能够在较宽的频带内获得低于-20dB的回波损耗。     

A Phase Domain Approach for Mitigation of Self-Interference in Wireless Transceivers

A novel approach for mitigation of self-interference in highly-integrated wireless transceivers is presented. Several examples of possible applications of this approach in a wireless cellular transceiver system-on-chip (SoC) are listed, and the application of one example is presented in detail. Mathematical analysis, simulation results, measurements, and implementation details are provided for the demonstrated technique, which was designed to minimize jitter induced onto the reference clock of a GSM transceiver's PLL. Excessive jitter on this clock, caused by multiple RF aggressors centered at harmonics of it, creates amplified in-band phase-noise at the RF output of the PLL, resulting in failures in the transmitter's performance. The identification of this highly complex interference mechanism, which represents a significant part of this work, is discussed in detail, as is the implemented solution. The presented phase-adjustment technique, leveraging specific features of the digitally intensive PLL and available digital-signal-processing resources, is demonstrated in a GSM system-on-chip (SoC) based on the Digital RF Processor (DRPtrade) technology in 90 nm CMOS. As it does not involve dedicated hardware, nor does it noticeably increase the current consumption, it represents a cost-free solution in the final product.     

Mitigating Near-field Interference in Laptop Embedded Wireless Transceivers

In laptop and desktop computers, clocks and busses generate significant radio frequency interference (RFI) for the embedded wireless data transceivers. RFI is well modeled using non-Gaussian impulsive statistics. Data communication transceivers, however, are typically designed under the assumption of additive Gaussian noise and exhibit degradation in communication performance in the presence of RFI. When detecting a signal in additive impulsive noise, Spaulding and Middleton showed a potential improvement in detection of 25 dB at a bit error rate of 10^− 5 when using a Bayesian detector instead of a standard correlation receiver. In this paper, we model RFI using Middleton Class A and Symmetric Alpha Stable (S αS) models. The contributions of this paper are to evaluate (1) the performance vs. complexity of parameter estimation algorithms, (2) the closeness of fit of RFI models to the measured interference data from a computer platform, (3) the communication performance vs. computational complexity tradeoffs in receivers designed to mitigate RFI modeled as Class A interference, (4) the communication performance vs. computational complexity tradeoffs in filtering and detections methods to combat RFI modeled as S αS interference, and (5) the approximations to filtering and detection methods developed to mitigate RFI for a computationally efficient implementation.     

一种基于多协议电流复用双频段压控振荡器的设计

.本文设计了一种基于IEEE 802.11 a/b/g和蓝牙多协议零中频收发机中双频段压控振荡器.该振荡器使用电流复用的方法,即将两个工作在不同频段的压控振荡器串联堆叠,达到了降低功耗的目的.通过Aglient ADS仿真,结果表明本文所设计的双频段压控振荡器功耗为12.22 mW,2.44和5.23 GHz载频处的相位噪声分别为-126.2和-120.1dBc/Hz@1 MHz,其性能完全符合IEEE 802.11a/b/g和蓝牙协议的要求.该振荡器将采用0.18 μm CMOS工艺实现,芯片面积为1.18 mm×0.67 mm.     

基于FDTD方法的无线信道衰落特性模拟研究

为了表述无线信道衰落的时变及远区分布特性，提出了利用时域有限差分(FDTD)方法研究由多径效应引起的时变无线信道衰落的方法。在此将无线信道的衰落建模为随机过程，而不是通常的确定性随机变量。首先基于Clarke统计模型，利用FDTD方法研究了时变无线信道的小尺度平坦衰落特征；然后利用Monte Carlo方法和FDTD方法产生了具有信道多普勒功率谱特性的色高斯随机过程，再基于无线信道的时变统计特性建模，用Suzuki模型研究了时变无线信道的快衰落；最后将无线信道衰落特性分布和理论分布做了比较，验证了方法的有效性。