造价项目管理信息系统的开发

自我国进入信息时代以来,信息技术在我国社会经济社会发展中的各个层面都起着十分重要的作用。由于我国造价项目信息化管理的起步较晚,使得对造价项目进行信息化管理时存在着严重的问题,这对于推动我国经济建设和加强对造价项目的管理十分不利。本主要对造价项目管理信息系统建设的需求分析,造价工程项目管理的原则以及造价项目管理信息系统开发进行研究。     

短波接收机便携式自动测试平台设计与实现

针对在测试短波接收机的性能指标时,需使用的测试仪器种类繁多、操作复杂等不足,开发了一种便携式自动测试平台。介绍了在测试平台中实现多种调制模式的射频信号以及对音频信号进行采集分析的方法,测试结果对比使用综测仪测试,误差＜0.1%,满足测试指标要求。     

信号源功率电平高准确度测量方法

对射频信号源的绝对电平和调谐射频电平的测量方法、测量仪器的配置选择、误差来源,以及测量不确定度等方面进行了综合分析和研究.     

多极化目标特性测量雷达测量接收机的设计

多极化目标特性的测量是现代雷达研究中的一个新课题。由于隐身和反隐身技术的不断深入，准确的目标特性测量显得十分重要。本文根据测量雷达自身的要求，结合实际应用给出了测量雷达测量接收机的组成，并对影响测量精度的几个因素进行了分析，以求得合理的设计。     

A Decision Aided CDMA Receiver with Partially Adaptive Decorrelating Multi-User Interference Cancellation

A CDMA receiver with enhanced multiple access interference (MAI) suppressionis proposed for a pilot symbols assisted system over multipath channels. Thedesign of the receiver involves the following procedure. First, blind adaptivecorrelators are constructed at different fingers based on the scheme ofgeneralized sidelobe canceller (GSC) to collect the multipath signals andsuppress MAI. A low-complexity partially adaptive (PA) realization of the GSCcorrelators is proposed which incorporates multi-user information for reducedrank processing. By a judiciously designed decorrelating procedure, a new GSCstructure is obtained in which the MAI are decorrelated and suppressedindividually. The next step is then a simple coherent combining of thecorrelator outputs with pilot aided channel estimation. Finally, furtherperformance enhancement is achieved by an iterative scheme in which the signalis reconstructed and subtracted from the GSC correlators input data, leadingto faster convergence of the receiver. The proposed low-complexity PA CDMAmulti-user receiver is shown to be robust to multipath fading and channelerrors, and achieve nearly the same performance of the ideal maximum SINR andMMSE receivers by using a small number of pilot symbols.     

改进最小费用流相位解包裹算法

在不同解包裹算法中,最小费用流(MCF)解包裹法可以限制残差点误差远程扩散,并将误差优先限制在低相干区域,有利于保证高相干区域解包裹结果不受干扰,精度较高,但残差点数量较多时计算效率很低.为缩短解包裹时间,提出一种残差点预处理方法.该方法将残差点视作正负电荷,通过电场力,引导距离较近的异号残差点互相抵消,大幅减少残差点...     

槽式聚光光伏-光热化学互补系统中吸热反应管性能研究

本文以槽式聚光光伏-光热化学互补系统为对象,并以甲醇裂解反应为例,探究了该系统内的吸热反应管在入射光谱仅为透过的红外光谱波段时的性能。研究结果表明,当几何聚光比为21.4时,透射到吸热反应管的红外光谱能量转化为太阳能燃料化学能的效率可达54%~58%。此外,还研究了太阳直射辐射强度、甲醇进口流量、甲醇进口温度等关键运行参数对吸热反应管中反应管温度、甲醇转化率等的影响。本文的研究工作为探索聚光光伏-光热化学互补方法提供了一种可能。     

The Development of a Dual Channel SIS Receiver of Trao Telescope

We developed a low noise dual channel receiver with 100GHz and 150GHz band, which is used to make the simultaneous observation with two bands. The SIS mixers are used in both bands. The constructed dewar for the receiver has a performance with a vacuum of 10^–8torr and a temperature of 4.2K. The receiver noise temperature is 50K(DSB) for 100GHz band and 80K(DSB) for 150GHz band, respectively. In order to achieve the simultaneous observations, the quasioptical system is precisely designed, and also evaluated by measurements in the laboratory. The relative pointing offset between two bands is 3. We have observed the various sources using the receiver since October 1998.     

EPON系统光收发电路设计

光收发技术是EPON系统的关键技术之一。在OLT端,发射驱动采用ADN2841、接收数据恢复采用ADN2809,结合单芯双向组件HWT-4324-14313S的方案。在ONU端,发射驱动采用ADN2841、接收数据恢复采用ADN2809,结合单芯双向组件HWT-3424-14313S的方案。测试结果表明,主要指标符合国际标准IEEE802.3ah。成功地解决了EPON系统光的突发、突收问题,可以广泛应用于光接入网系统中。     

红外触控屏的接收单元抗干扰新技术及其验证

红外触摸屏通过发射接收红外光进行工作,对环境光照因素的变化比较敏感。在有外界强光照的环境中使用红外触摸屏会受到极大干扰,导致红外接收管接收到的光强发生异常,从而引起误动作。本文研究了采用高频红外光的发射与接收,以锁相放大方式滤除太阳光的干扰频段分量,实现了红外触控屏的抗直接照射的阳光干扰的方法与验证结果。此外,通过改进了锁相放大器的解调算法,去掉传统的锁相放大后级所必须的滤波电路,电路更加简洁、可靠。经硬件平台的实际验证,选频Q值可以达到145.985,并能在50 000lx的光强下正常工作。该算法能够实现很好的选频和抗强光效果,达到抗干扰目的。