And one of the basic difficulties lies in the complexity of the fault models in the analog system since both the input stimulus and output response are continuous variables , and the parameters in the circuit components are also continuous too 难点之一是模拟电路中的输入激励和输出响应都是连续量,电路中元件的参数通常也是连续的,所以模拟系统中的故障模型比较复杂,难以作简单的量化。
The research on the fault diagnosis of analog system is one of the most popular foreland problem at present time and even in the future , that is because the reliability of the electronic system is dependent on the anlog circuits , which has a very important practical significance 模拟系统故障诊断课题是一个现阶段及将来被广泛关注的前沿课题之一,模拟电路的可靠性决定了电子设备系统的可靠性,具有重要的实际意义。
Due to the higher demand of speed and precision of dsp , the intermediate frequency ( if ) digitalization receiver which is compared with analog system takes on the advantage of small volume , light weight , low cost , simple configuration , and easy integration . so that digitalization at if is current trend of communication and radar development , the traditional analog receiver is now being replaced by digital receiver gradually 由于对信号处理的速度、精度要求不断提高,而中频数字接收及信号处理系统与模拟系统相比,具有易于dsp算法编程实现、体积小,重量轻,造价低、结构简单,易模块化、系统配置更新快、维护升级方便等优点,所以,雷达信号接收机及处理机的中频数字化系统近年来备受重视,已经逐渐取代传统的模拟接收机。
Considering the fact that the analog system is not so good as the digital system on the respect of variation of bandwidths and on the respect of switch between different bandwidths . this paper proposes to adopt the dds ( direct digital synthesis ) technique that produces chirp signals of different bandwidths to improve the situation of losing tracks for the ocean satellite altitude indicator in measuring coarse surfaces 现在的雷达基本上采用模拟系统产生线性调频信号,由于模拟系统在带宽变化方面和不同带宽间切换方面不如数字系统,本文采用dds ( directdigitalsynthesis )技术产生不同带宽的线性调频信号以改善海洋卫星高度计在测量粗糙表面时存在的失锁现象。
In this paper , a high integrated and intelligent digital dsp - spm system is developed based on the nspm6800 spm manufactured by the beijing zhongke mechanical & electrical equipment co . at present , the pc of spm system is burdened with not only sending and receiving data , but also disposing of image , which hinders the enhancement of speed of the system . in addition , as the function of spm is expanding , including tappingmode afm , efm , mfm , scm , etc , one hand , it amplifies the range of the application of spm , on the other hand it also means that the task of autocontrol and data transfer heavier . the advantages offered by the dsp compared to analog systems include considerable flexibility in the choice of the signal processing algorithm and greater ease in managing control parameters by the host computer , which are very important for the improvement of spm 本课题以北京市中科机电设备公司的nspm - 6800型扫描探针显微镜为基础,重新设计了以dsp为控制核心的控制系统,主要解决原系统存在的以下问题: ( 1 ) pc机既要实时控制数据的采集与发送,又要进行图像的后处理,整个系统的实时性难以达到要求; ( 2 )随着spm功能的扩展,一方面包括轻敲式原子力显微镜、电场力、磁场力、扫描容场显微镜等技术在内的spm技术扩展了仪器的测试范围和功能,另一方面也意味着自动控制量的增加和数据处理量的增加; ( 3 ) 16位a d 、 d a都采用的是购买的板卡,也通过isa槽插在pc机内,成本高,不利于扩展; ( 4 )另外,数字板通过isa槽插在pc机内,易受于扰,而且给安装带来不便。
But during this interim , there are so many old analog systems still working in companies and governments . it is impossible to establish a new digital network system instead of using the old one , for it is not practical and will cause a large waste of resource 然而,现阶段仍然处在从模拟系统到数字系统过渡的阶段,在众多的企事业单位和政府部门中,还有大量的模拟系统在运行,把他们全部推倒,重新建设全新的数字化网络化系统显然是不现实和不可取的,将造成固有资源的巨大浪费。
The main purpose of this paper is to research on the diagnosis of the analog circuit with tolerance based on parameter identification , it try to find a novel method of the fault diagnosis of the analog system . in this paper , a procedure for the multifrequency fault diagnosis of analog circuits is presented . generally speaking , for the diagnosis equations are nonlinear , it ’ s very difficult to solve them with high precision 本文的研究重点在于具有容差模拟电路故障诊断的参数识别方法,探索解决模拟电路故障诊断问题的新途径,介绍了由电路结构来提取故障诊断方程的多频支路和多频节点方法,由于故障诊断方程一般情况下是非线性的,因此,传统的非线性方程求解方法存在精度不高,计算困难的缺点。
With the develop of computer techniques , the digital autopilot system has replaced the analog system . the analog system has not been able to adapt the developmental desire of modem autopilot system function . the digital autopilot system , of which the computre is main part , has put up tremendous superiority in aspect of flight control system 随着计算机技术的发展,数字式飞行控制系统逐步代替了模拟式系统。模拟式系统已不能适应现代飞控系统功能发展的要求,而以计算机为主的数字式系统却在飞行控制方面表现出其巨大的优越性。