取样鉴相数字合成器环中的混沌动力学行为

分析和研究取样鉴相数字合成器环中的混沌动力学行为,根据Ushio与Hira等人的方法,从理论上证明了当系统参数满足一定条件时,系统会出现分岔现象,并具体计算出系统在各个不动点处的Hopf分岔集、系统的李雅普诺夫指数以及豪斯道夫维数。通过对系统进行计算机模拟,观察到系统的奇异吸引子,奇异吸引子的自相似性,系统在混沌状态下对初始条件的灵敏依赖性,进一步证实了三角形取样鉴相数字合成器环中存在混沌现象。

三角形取样鉴相数字合成器锁相环中的混沌

研究三角形取样鉴相数字合成器锁相环中的混沌现象。其方法是先对三角形取样鉴相数字合成器锁相环系统作离散化处理,得到相应的离散化系统模型;系统中的环路滤波器采用RC积分滤波器,鉴相器采用三角形鉴相特性;通过验证离散化系统相应的低维系统存在快返反射点,证明了当系统方程满足一定条件时,原系统有混沌输出。最后导出了混沌与系统参数间的关系式。

Design of remote ultrasonic signal generating system based on Kinetis60 and AD9951

A kind of remote ultrasonic generating system is designed in this paper.Microcontroller unit(MCU)Kinetis60and direct digital synthesizer(DDS)AD9951constitute the core section of this ultrasonic generating terminal in this system.A friendly and easy-operating host computer software is contrived to control the terminal to generate sinusoidal,rectangular and triangular waveform with variable frequency,amplitude and phase through ZigBee wireless transmission protocol.In order to enhance the practical driving ability,this system also includes power amplifier circuit and transformer matching design,which enable the ultrasonic generating terminal to output enough power for applying to different types of ultrasonic energy convertors.Through experimental verification,the host computer can precisely and swiftly control the ultrasonic generating terminal to generate the above three waveforms with variable wave elements.Oscilloscope is used to verify the terminal output performance of this remote system.