Dispersion Compensation in Externally Modulated Transmission System Using Chirped Fiber Grating

We present an externally modulated NTSC AM-VSB erbium-doped fiber amplifier (EDFA)-repeated system in the 1550 nm region which uses a chirped fiber grating (CFG) as a dispersion compensation device. In contrast to the conventional externally modulated fiber optical CATV systems, either with or without dispersion compensation fiber (DCF), good performances of carrier-to-noise ratio (CNR) ≥50 dB, composite second order (CSO) ≥74 dB, and composite triple beat (CTB) ≥65 dB were achieved for the full channel band after a 100-km single-mode fiber (SMF) transmission.     

基于PCI总线的矩阵电路在压变温压补偿系统中的实现与应用

本文提出基于PCI总线驱动控制的矩阵电路在压力变送器温压补偿系统中应用的目的是解决现有压力变送器温压补偿系统中HART总线型工位电路数量少,整套矩阵电路缺失冗余性,以及现有电路在压力变送器产品温压补偿中实用性差、维护成本高的问题。文中阐述的矩阵电路是以PCI总线为基础,实现对PIO数字接口卡的驱动控制,完成由PCI总线上32路数字I/O到168路数字I/O的转换,并利用168路数字I/O进行继电器矩阵电路设计,实现了弱电控制强电的过程,成功有效的解决了现存压力变送器温压补偿系统中矩阵电路存在的问题。该研发成果已经应用于PDS压力变送器产品温压补偿生产线上,并且该电路的设计能够满足压力变送器生产企业的需求,而且整套电路融入系统中能够长期稳定、可靠的运行。     

移动通信系统中的最优功率控制算法

本文研究了移动通信系统中的功率最优控制问题.我们首先将这一个工程问题转化为最大可满足线性不等式组问题的一个特殊情形,然后通过对这个组合优化问题的最优解的性质研究,给出了求解该问题的多项式时间算法.     

Long-Distance Transmission of AM-VSB CATV Systems Using Fabry-Perot Laser Diode and Fiber Bragg Grating

This study presented a directly modulated 1550 nm NTSC AM-VSB CATV longdistance transmission system using Fabry-Perot laser diode, optical isolator, fiber Bragg grating, quarter-split-band, and wavelength-division multiplexing techniques. Good carrier-to-noise ratio ( ≥48 dB), composite second-order ( ≥64 dB), and composite triple-beat ( ≥60 dB) performances were obtained after a 100 km standard single-mode fiber transmission. Our proposed system does not use an externally modulated 1550 nm transmitter and a sophisticated stimulated Brillouin scattering suppression technique. It reveals a prominent technique with simpler and more economical advantages than that of externally modulated 1550 nm transmission system.     

基于STM32的温湿度变送器设计

针对目前常见的电流型温湿度变送器恒流输出特性较差、精度较低、校准繁琐的不足,给出了一种基于STM32单片机的温湿度变送器设计方案。该电路以STM32单片机为控制核心,以SHT11数字式温湿度传感器采集环境温湿度。通过STM32的内部12位D/A输出模块将温湿度转换为模拟电压信号。随后,该电压信号通过V/I转换电路变为4～20mA的模拟电流信号。研究了常见V/I转换电路的原理并提出改进电路方案。最后,基于STM32的内部FLASH存储功能给出了一种上位机软件校准方案。通过对比仿真和实验表明,该变送器具有成本较低、恒流特性较好、精度较高、校准快捷方便的优点,能够满足工农业生产中常规温湿度测量的要求。     

4.25 Gbps小型可热插拔光收发模块的设计与测试

对4.25 Gbps小型化可热插拔(SFP)光收发模块的关键参数进行了理论分析,从发射、接收和控制3个方面讨论了模块的结构组成,设计出了符合SFP MSA及SFF-8472协议的光模块,并根据此设计方案制作了样品模块。在-40,25,85 ℃环境温度下测试和分析了模块的性能指标,结果显示其光功率、消光比和灵敏度等均符合设计要求,且在适用温度范围内表现出良好的稳定性。实验证实了方案的可行性,为模块的产品化提供了参考。     

多波长光标记交换中一种新的多波长-时间编码法

首先介绍了多波长光标记分组交换的基本原理,并针对多波长光标记分组交换中的标记头编码法,提出了一种新的多波长-时间编码法,这种编码法充分利用了波长和时间两种自由度,大大增加了编码数量,提高了编码效率.最后,设计了实现这种编码的发射机和接受装置.     

High-Performance Fiber-Optic Link for Electronic Countermeasure Antenna Remoting

The ability to remotely radiate microwave signals has become an essential feature of modern electronic countermeasure (ECM) systems. The use of fiber optics allows remote microwave links to be constructed that have very low propagation loss and dispersion, are very flexible and light in weight, and have a high degree of immunity from external electromagnetic fields, cross talk, and environmental effects. This combination of desirable characteristics is beneficial to avionic ECM antenna remoting as well as many other applications. GEC-Marconi has developed high-per formance fiber components for use in a towed radar decoy. The resulting rugged and compact optical transmitter and receiver modules have been proven to maintain the required performance over the full hostile range of environmental conditions en countered on a fast jet. Packaged fiber-optic links have been produced that can achieve a compression dynamic range of 87 dB in a 1-MHz bandwidth over a 2- to 18-GHz range.     

Dispersion Compensation in Externally Modulated Transmission System Using Chirped Fiber Grating

We present an externally modulated NTSC AM-VSB erbium-doped fiber amplifier (EDFA)-repeated system in the 1550 nm region which uses a chirped fiber grating (CFG) as a dispersion compensation device. In contrast to the conventional externally modulated fiber optical CATV systems, either with or without dispersion compensation fiber (DCF), good performances of carrier-to-noise ratio (CNR) S 50 dB, composite second order (CSO) S 74 dB, and composite triple beat (CTB) S 65 dB were achieved for the full channel band after a 100-km single-mode fiber (SMF) transmission.