基于ML7338的小灵通智能中继站设计与实现

介绍了一种基于ML7338的新型小灵通智能中继站的设计与实现,完成了该系统的硬件模块设计和软件设计及编译,并对软件流程进行了详细的介绍.该系统主要采用小灵通芯片ML7338(ARM7TDMI核)和RDA5206射频模块,实现高性能,低成本.所设计的智能中继站能实现对PHS信号的存储与转发,能够有效解决当前小灵通网络的盲区问题,同时对边远地区的网络扩展也可起到补充作用.     

GPS射频信号源的设计与实现

在研究GPS信号结构的基础上,给出了GPS射频信号源的设计方案,并分模块进行了设计与实现.实验结果表明,基带/中频模块实现了GPS信号的BPSK调制和扩频调制,输出数字中频信号;射频模块实现了上变频功能,完成了信号的射频调制.     

基于2．4GHz／900MHz双射频蓝牙模块的研究与实现

提出了一种基于2.4GHz/900MHz双射频蓝牙模块的研究与实现方案。该方法通过双射频通信模式来解决短距离无线通信中日益严重的共扰问题,为之提出了全新的解决思路。在不改变蓝牙基带协议的基础上,增加蓝牙900MHz射频模块,使得蓝牙设备的射频部分可在2.4GHz或900MHz的ISM频段间切换。实验结果表明,对于双射频的蓝牙系统来说,其不仅改善了与其他无线通信方式的相互干扰问题,而且还从蓝牙通信距离方面得到了改进。     

数据传输系统的FPGA一体化设计与实现

当前的差分相移键控（DPSK）数据传输系统大多是采用独立的数据调制解调终端设备和收发信设备组成的,集成度低、可靠性较差,存在内部信号量化噪声。通过应用现场可编程门阵列（FPGA）加高速数字信号处理设计技术,将数据传输系统中的信号进行DPSK调制,基带到射频信号的数字上变频,以及信号的解调与射频到基带信号数字下变频进行一体化设计,解决了DPSK调制解调终端设备与射频信道设备相互独立所带来的集成度低、可靠性差,以及设备间信号变换引起信号受损等问题。     

SAR目标回波基带信号产生模块设计

SAR目标回波基带信号产生模块是SAR目标回波模拟器的关键单元之一,其设计影响到模拟器系统的性能.该文提出了一种SAR目标回波基带信号产生模块的设计方案,详细介绍了该模块的主要功能、工作原理、模块组成以及实现方法,并提供了该模块的测试结果.经验证,它达到了SAR目标回波基带数据高速传输和大容量存储的设计要求,满足模拟器的研制需要.     

关于PHS网络与3G网络融合的探讨

文章首先简要介绍了当前小灵通网络发展情况和小灵通网络的网络构架.针对3G脚步的临近,文章结合PHS网络和3G网络的特点,重点就如何构建优势互补的紧密融合的PHS与3G混合网络作详细的探讨.文章还提出了改造PHS网络实现与3G共核心网的建议,实现"一机一号双模双卡"手机终端.同时在3G的编号允许的情况下,保护PHS老用户享受3G服务.在无线方面,文章对PHS与3G无线射频兼容性方面作了简要的说明.     

一种低功耗高频RFID标签芯片基带控制器

设计了一款应用于高频射频识别标签芯片的基带控制器。该基带控制器符合ISO15693标准协议,满足无源射频识别标签的低成本、低功耗的需求。详细论述了解码电路、命令响应模块及状态机、数据组织模块等关键电路的设计。芯片采用中芯国际0.35μm2P3M嵌入式EEPROM的混合信号CMOS工艺实现,基带控制器的Core面积仅为0.23mm2,功耗低至66.8μW。     

ADF4360—4原理及其在GPS信号源中的应用

通过分析频率合成器ADF4360—4的工作原理、性能特点及其典型应用,提出一种以FPGA芯片和频率合成器ADF4360—4为核心的GPS信号源系统,给出了总体及模块设计方案,并分模块进行了设计与实现。测试结果表明,以FPGA芯片为核心的基带／中频模块完成了GPS信号的BPSK调制和扩频调制,实现了GPS数字中频信号输出;以频率合成器ADF4360—4为核心的射频模块完成了上变频功能,实现了信号的射频调制。     

R&S公司数字基带测试解决方案

随着无线通信的快速发展,越来越多设备在产品的设计中分为基带处理单元和射频处理单元,模拟接口逐渐被数字IQ接口替代。罗德与施瓦茨公司对数字基带接口测试拥有丰富的实际经验,包括数字基带模块整机测试以及现场日常维护测试。本文着重介绍数字基带模块的测试方案。     

关于PHS网络与3G网络融合的探讨

文章首先简要介绍了当前小灵通网络发展情况和小灵通网络的网络架。针对3G脚步的临近，文章结合PHS网络和3G网络的特点，重点就如何构建优势互补的紧密融合的PHS与3G混合网络作详细的探讨。文章还提出了改造PHS网络实现与3G共核心网的建议，实现“一机一号双模双卡”手机终端。同时在3G的编号允许的情况下，保护PHS老用户享受3G服务。在无线方面，文章对PHS与3G无线射频兼容性方面作了简要的说明。     

波导传输检波装置的研究

波导传输检波装置用以发射机的检波式功率监测,是雷达导引头发射机的一个重要组成部分。发射机产生的大功率射频信号经过波导传输检波装置最终传输给天线,在大功率传输过程中,波导传输检波装置从大功率射频信号中耦合出一定量进行射频信号包络检波,检波信号通过外围电路处理可以反映发射机工作状态,并可反馈优化发射机工作状态。文中介绍了波导传输检波装置的设计原理,并对设计中的一些重要环节进行了仿真,其中包括了温度对设计的影响。     

Review: Machine learning techniques in analog/RF integrated circuit design,synthesis, layout,and test

Rapid developments in semiconductor technology have substantially increased the computational capability of computers. As a result of this and recent developments in theory, machine learning (ML) techniques have become attractive in many new applications. This trend has also inspired researchers working on integrated circuit (IC) design and optimization. ML-based design approaches have gained importance to challenge/aid conventional design methods since they can be employed at different design levels, from modeling to test, to learn any nonlinear input-output relationship of any analog and radio frequency (RF) device or circuit; thus, providing fast and accurate responses to the task that they have learned. Furthermore, employment of ML techniques in analog/RF electronic design automation (EDA) tools boosts the performance of such tools. In this paper, we summarize the recent research and present a comprehensive review on ML techniques for analog/RF circuit modeling, design, synthesis, layout, and test.     

RF and IF ports matching circuit synthesis for a simultaneousconjugate-matched mixer using quasi-linear analysis

A quasi-linear two-port approach between RF and IF ports to design a simultaneous conjugate-matched mixer is presented in this paper. Conventionally, mixer design is treated as a nonlinear three-port device problem. Nonetheless, with the exception of the large-signal local oscillator (LO) that exists at the LO port, the input RF and output IF signals that exist at the RF and IF ports, respectively, are small signals. Consequently, mixers can be approximated as bilateral quasi-linear two-port circuits with a time-variant transfer function between the RF and IF ports, in which the LO port of the mixer is treated as part of the two-port network. With this approximation, it can be shown mathematically that the optimum source and load matching networks required for attaining simultaneous conjugate match at the RF and IF ports are actually time invariant, thus implying that it is possible to synthesize these optimum impedance values. This proposed mixer design technique, together with the equations derived, are verified with block-diagram simulation and experimental measurements of two 2.4-GHz RF/420-MHz IF double-balanced diode mixers     

Robotics-Based Location Sensing Using Wireless Ethernet

A key subproblem in the construction of location-aware systems is the determination of the position of a mobile device. This article describes the design, implementation and analysis of a system for determining position inside a building from measured RF signal strengths of packets on an IEEE 802.11b wireless Ethernet network. Previous approaches to location-awareness with RF signals have been severely hampered by non-Gaussian signals, noise, and complex correlations due to multi-path effects, interference and absorption. The design of our system begins with the observation that determining position from complex, noisy and non-Gaussian signals is a well-studied problem in the field of robotics. Using only off-the-shelf hardware, we achieve robust position estimation to within a meter in our experimental context and after adequate training of our system. We can also coarsely determine our orientation and can track our position as we move. Our results show that we can localize a stationary device to within 1.5 meters over 80% of the time and track a moving device to within 1 meter over 50% of the time. Both localization and tracking run in real-time. By applying recent advances in probabilistic inference of position and sensor fusion from noisy signals, we show that the RF emissions from base stations as measured by off-the-shelf wireless Ethernet cards are sufficiently rich in information to permit a mobile device to reliably track its location. An earlier version of this article was published as A.M. Ladd, K.E. Bekris, A. Rudys, G. Marceau, L.E. Kavraki and D.S. Wallach, Robotics-based location sensing using wireless Ethernet, at the 8th ACM International Conference on Mobile Computing and Networking (MOBICOM) (September 2002, Atlanta, GA).     

Direct downconversion of multiband RF signals using bandpass sampling

Abstract-Bandpass sampling can be used by radio receivers to directly digitize the radio frequency (RF) signals. Although the bandpass sampling theory for single-band RF signals is well established, its counterpart for multiband RF signals is relatively immature. In this paper, we propose a novel and efficient method to find the ranges of valid bandpass sampling frequency for direct downconverting multiband RF signals. Simple formulas for the ranges of valid bandpass sampling frequency in terms of the frequency locations of the multiple RF bands are derived. The result can be used to design a multiband receiver for software defined radios.     

Direct bandpass sampling of multiple distinct RF signals

A goal in the software radio design philosophy is to place the analog-to-digital converter as near the antenna as possible. This objective has been demonstrated for the case of a single input signal. Bandpass sampling has been applied to downconvert, or intentionally alias, the information bandwidth of a radio frequency (RF) signal to a desired intermediate frequency. The design of the software radio becomes more interesting when two or more distinct signals are received. The traditional approach for multiple signals would be to bandpass sample a continuous span of spectrum containing all the desired signals. The disadvantage with this approach is that the sampling rate and associated discrete processing rate are based on the span of spectrum as opposed to the information bandwidths of the signals of interest. Proposed here is a technique to determine the absolute minimum sampling frequency for direct digitization of multiple, nonadjacent, frequency bands. The entire process is based on the calculation of a single parameter-the sampling frequency. The result is a simple, yet elegant, front-end design for the reception and bandpass sampling of multiple RF signals. Experimental results using RF transmissions from the US Global Positioning System-Standard Position Service (GPS-SPS) and the Russian Global Navigation Satellite System (GLONASS) are used to illustrate and verify the theory     

DSP-Driven Self-Tuning of RF Circuits for Process-Induced Performance Variability

In the deep-submicrometer design regime, RF circuits are expected to be increasingly susceptible to process variations, and thereby suffer from significant loss of parametric yield. To address this problem, a postmanufacture self-tuning technique that aims to compensate for multiparameter variations is presented. The proposed method incorporates a “response feature” detector and “hardware tuning knobs,” designed into the RF circuit. The RF device test response to a specially crafted diagnostic test stimulus is logged via the built-in detector and embedded analog-to-digital converter. Analysis and prediction of the optimal tuning knob control values for performance compensation is performed using software running on the baseband DSP processor. As a result, the RF circuit performance can be diagnosed and tuned with minimal assistance from external test equipment. Multiple RF performance parameters can be adjusted simultaneously under tuning knob control. The proposed concepts are illustrated for an RF low-noise amplifier (LNA) design and can be applied to other RF circuits as well. A simulation case study and hardware measurements on a fabricated 1.9-GHz LNAs show significant parametric yield enhancement (up to 58%) across the critical RF performance specifications of interest.      

一种基于FPGA的直接数字射频上变频方案

传统模拟器件实现射频(RF)上变频方法存在硬件复杂度高,灵活性差,功耗大等缺点。随着半导体器件的发展,软件无线电要求将上变频中射频或中频的信号处理尽量往基带数字信号处理靠拢。本文利用多相滤波器原理,提出一种基于现场可编程门阵列(FPGA)的直接数字RF上变频架构和实施方案,并且通过软硬件仿真验证了该方案的可行性。     

基于ZigBee技术的公共场所无线温度采集系统

讨论基于ZigBee无线网络技术的温度采集系统的实现方案。系统的实现基于ZigBee解决方案Chipcon公司的无线射频芯片CC2420加Microchip公司的PIC18F4620微处理器,以及DALLAS公司生产的单线数字温度传感器DS18B20。详细讨论硬件设计和软件设计。系统有效地实现了对公共场所空调温度的采集和监督,并且成本低廉,终端节点功耗低,达到了节能减排的目的。