对JTIDS干扰的三种方法

如何对JTIDS进行有效干扰是电子战技术发展中的一个难题.在分析JTIDS特点的基础上,重点对JTIDS的有效干扰方法进行了研究.针对宽带拦阻式干扰和转发式干扰的优缺点,提出采用宽带拦阻式干扰 伪码相关干扰的组合干扰方式来对抗JTIDS,它可在不增加干扰功率的情况下对同一地区的所有JTIDS实施有效干扰.研究结果对我军信息化作战具有一定的参考价值.     

广播电视卫星的工作原理

主要介绍广播电视卫星的基本原理和系统组成.     

双向式测距系统性能最优化研究及其应用

双向式激光测距技术克服传统激光测距系统中距离四次方能量衰减的缺点,可用于行星际高精度激光测距。通过研究双向式激光测距系统中资源和采样率之间的平衡性,可以用适量减少星端资源,增加地面端资源的方法,来达到测距性能最优化。以平衡系统为基础,开展双向式激光测距模拟试验,进而评估上海天文台卫星激光测距系统的行星际测距能力。最后介绍了2005年美国对水星的试验系统MLA。     

基于无源标签的远距离射频识别系统

通过RFID阅读器将标签对标签中的信息进行收集,然后将信息传送到操作应用系统中去,从而得知标签内容。虽然有源标签的传输距离要大于无源标签,但是考虑到设计成本及系统的广泛使用,于是文中通过标签依靠阅读器发送过来的载波将存储的信息发送到阅读器,再由内嵌在阅读器中的ZigBee,传送给作为协调器的ZigBee模块后送往应用系统中去,通过无源RFID和ZigBee来建立远距离的模型,达到扩大射频覆盖范围的功能。     

A CMOS multichannel electrical stimulation prototype system

We developed an inductively powered integrated electronic prosthesis, allowing for the trade‐offs among implant functionality, circuit complexity, power consumption, hardware cost, and integrity of data recovery, for a multichannel microstimulation circuitry. The proposed prosthesis features energy efficiency and is capable of up to 40 scan/s with 240 stimulus channels in mode I and three times resolution at the same scan rate in mode II under a carrier frequency of 2 MHz. In order to satisfy future upgrade demands, the prototype has been constructed with a 16‐channel‐based stimulation scheme so that the spatial resolution of the design can be extended toward various experimental purposes. The circuit techniques used in the system are detailed. Results from fabricated chips using a 0.18‐µm CMOS process are given as proof of concept. Copyright © 2011 John Wiley & Sons, Ltd.     

采用动态带宽提高技术的用于无源超高频RFID标签的供电系统

This paper presents a voltage regulator system for passive UHF RFID transponders,which contains a rectifier,a limiter,and a regulator.The rectifier achieves power by rectifying the incoming RF energy.Due to the huge variation of the rectified voltage,a limiter at the rectifier output is used to clamp the rectified voltage.In this paper,the design of a limiter circuit is discussed in detail,which can provide a stable limiting voltage with low sensitivity to temperature variation and process dispersion.The key aspect of the voltage regulator system is the dynamic bandwidth boosting in the regulator.By sensing the excess current that is bypassed in the limiter during periods of excess energy,the bias current as well as the bandwidth of the regulator are increased,the output supply voltage can recover quickly from line transients during the periods of no RF energy to a full blast of RF energy.This voltage regulator system is implemented in a 0.18 μm CMOS process.     

Implementing electronic identification for performance recording in sheep: II. Cost-benefit analysis in meat and dairy farms

Costs and secondary benefits of implementing electronic identification (e-ID) for performance recording (i.e., lambing, body weight, inventory, and milk yield) in dairy and meat ewes were assessed by using the results from a previous study in which manual (M), semiautomatic (SA), and automatic (AU) data collection systems were compared. Ewes were identified with visual ear tags and electronic rumen boluses. The M system used visual identification, on-paper data recording, and manual data uploading to a computer. The SA system used e-ID with a handheld reader in which performances were typed and automatic uploaded to a computer. The use of a personal digital assistant (PDA) for recording and automatic data uploading, which transformed M in a SA system, was also considered. The AU system was only used for BW recording and consisted of e-ID, automatic data recording in an electronic scale, and uploading to a computer. The cost-benefit study was applied to 2 reference sheep farms of 700 meat ewes, under extensive or intensive production systems, and of 400 dairy ewes, practicing once- or twice-a-day machine milkings. Sensitivity analyses under voluntary and mandatory e-ID scenarios were also included. Benefits of using e-ID for SA or AU performance recording mainly depended on sheep farm purpose, number of test days per year, handheld reader and PDA prices, and flock size. Implementing e-ID for SA and AU performance recording saved approximately 50% of the time required by the M system, and increased the reliability of the data collected. Use of e-ID increased the cost of performance recording in a voluntary e-ID scenario, paying only partially the investment made (15 to 70%). For the mandatory e-ID scenario, in which the cost of e-ID devices was not included, savings paid 100% of the extra costs needed for using e-ID in all farm types and conditions. In both scenarios, the reader price was the most important extra cost (40 to 90%) for implementing e-ID in sheep farms. Calculated extra costs of using the PDA covered more than 100% of the implementation costs in all type of sheep farms, indicating that this device was cost-effective for sheep-performance recording.     

无源超高频射频识别标签中浅调制信号的检测

In a typical RFID system the reader transmits modulated RF power to provide both data and energy for the passive transponder. Low modulation index RF energy is preferable for an adequate tag power supply and increase in communication range but gives rise to difficulties for near-field conventional demodulation. Therefore, a novel ASK demodulator for minimum 20% modulation index RF signal detection over a range of 23 dB is presented. Thanks to the proposed innovative divisional linear conversion from the power into voltage signal, the detection sensitivity is ensured over a wide power range with low power consumption of 8.6 μW. The chip is implemented in UMC 0.18μm mix-mode CMOS technology, and the chip area is 0.06 mm^2.     

某型空管应答机高度源模拟器电路设计

介绍了基于FPGA的某型空管应答机高度源信号模拟器的电路设计过程,主要包括飞机高度数据的编码和格式、系统硬件结构和工作流程以及FPGA功能模块设计和VHDL编程实现等,并通过了Active HDL 6.1的仿真验证。提出的数据转换算法节约了FPGA芯片资源,转换速度快,延时小。系统功能改进和升级十分方便,稳定性好、可靠性高、成本低廉。     

基于51单片机的无线识别装置系统

介绍一种简单射频识别系统设计.该设计包括阅读器、应答器和线圈3部分.由单片机控制阅读器向应答器发射无线信号.并接收应答器回送的信号,再通过分析回送信号识别物品.阅读器和应答器之间以半双工通信方式通信.