Abstract : a new technology of frequency tracking and synchronizing is given in this paper at the first time . this technology is digital non - temporarystate frequency tracer , in which digital and logical circuit is adopted to accomplish frequency - tracking and synchronizing accurately . it has some advantages such as simple circuit , adjustable relationship of inpur and output , no temporart state procedure , so this technology has wide application foreground in electrical technology and modern communication field 文摘:提出一种新的频率跟踪技术? ?数字式无暂态频率跟踪器，该技术采用数字逻辑电路实现了频率精确同步跟踪，具有电路简单、输入输出频率关系可调、没有暂态过程等优点，在电子技术和现代通信等科技领域具有广泛的应用前景。
The distortion introduced by switching power amplifier is typically larger than in their linear counterparts due to intrinsic nonlineariry of switching converter . one of the key factors of affecting fidelity of switching power amplifier is control technique . one cycle control theory developed since 1990s is a large signal nonlinear pwm technology , which basic concept is to force the average of the controlled switch - variable to be equal or proportional to the control reference in each switching cycle . one cycle control technique features the merit of simple circuit structure , high control precision , fast dynamic response , and control performance not affected by the variable of power parameters . it is very suitable to control switching power amplifier 控制技术是影响开关功率放大器保真度的关键因素之一。单周控制理论是20世纪90年代初提出的一种大信号、非线性pwm控制技术，其基本控制思想是保证在每一个开关周期中开关变量与控制参考量相等或成比例。它具有结构简单、控制精度高、响应速度快，控制性能不受电源参数变化影响等优点，因此非常适合于控制开关功率放大器。
This regulator can generate output voltage as high as 12v with wide input voltage range of 2 . 6v to 5 . 5v . it has the advantages of high - precision , simple circuit , low power consumption , wide temperature range of - 25 to 85 and 90 % high convert efficiency . at the same time , the ic has two switching frequencies ( 640khz or 1 . 2mhz selectable ) , under - voltage protection and programmable soft - start 该芯片采用0 . 6微米bcd工艺制程,在2 . 6v 5 . 5v的输入电压范围内可实现高达12v的升压功能,工作温度范围为- 25 85 ,转换效率达到90 % ,具有实现电路简单、输出电压精度高、功耗低等优点。
Continuous - time filter needn ’ t a / d switch , data processing , d / a switch technique and so on to finish filtering function with analog signal like digital filter . and it needn ’ t switch action to sample data in the discrete time with analog signal like switched capacitor filter . so continuous - time filter has several advantages , such as high processing speed , simple circuit configuration , and low power consumption 对每种方法都进行了详细的推导,总结了每种设计方法的设计步骤、适用场合,举例用每种设计方法对具体滤波器进行了电路设计、灵敏度特性分析、失真特性分析等,并用计算机仿真验证了电路方案。
