摘要
基于锁相放大技术的颗粒检测需要频率范围宽、移相精度高的移相信号源。针对现有的移相信号源在高频范围移相精度低的缺点,设计了采用直接数字频率合成技术,以2片AD9852为核心的移相信号源,给出了系统硬件设计原理。重点介绍了高精度移相、幅度闭环控制的软硬件设计。实验结果表明:该系统在保证宽频范围的同时,输出信号在相位差、频率、幅度方面都具有较高的精度,满足颗粒检测的要求。
Particle detection based on lock-in amplifier needs phase-shift signal generator with wide frequency range and high phase shift precision. Since the traditional phase-shift signal generator has the default of low precision in high frequency range, a novel one was designed based on direct digital frequency synthesis technology and it adopts two AD9852 chips as its core. Hardware design of the system was put forward. The units of high precision phase shift and amplitude closed-loop control were analyzed. The experiment results show that the output signal of the system has high accuracy in phase difference, frequency and amplitude in wide frequency range and it meets the demand of particle detection.
出处
《仪表技术与传感器》
CSCD
北大核心
2009年第4期102-104,共3页
Instrument Technique and Sensor
关键词
移相信号源
AD9852
锁相放大
颗粒检测
phase shift signal generator
AD9852
lock-in amplifier
particle detection
