为了实现对中国散裂中子源(CSNS)/快循环同步加速器(RCS)射频系统中高频加速电压和束流两个同步变化的快循环扫频信号之间相位差的精确测量,需要选择合适的信号采集方案与相位差测量算法.介绍了常用的同频信号相位差测量算法,讨论了不同相位差测量算法的特点与适用性;详细描述了快速傅里叶变换(FFT)交叉谱法与加余弦窗FFT插值法两种相位差测量算法的原理.为了研究这两种算法在扫频信号测量中的适用性,利用NI的虚拟仪器技术以及Labview图形化编程技术,搭建扫频信号相位差测量系统,对这两种相位差测量算法进行仿真模拟.仿真结果表明,加余弦窗FFT插值算法可以满足快循环扫频信号相位差测量精度的要求.

In order to precisely measure the phase difference between two sweeping signals with rapid cycling mode,it is necessary to select a method of signal acquisition and phase difference measurement algorithms for the RF accelerated voltage of the CSNS/RCS (China Spallation Neutron Source/Rapid Cycling Synchrotron) RF system and beam signal.The frequencies of both signals change synchronously.In this paper,measurement algorithms of signals with the same frequency are introduced and the features and applicability of those algorithms are discussed.Secondly,two different FFT spectrum analysis algorithms are elaborated and compared,including FFT cross-spectral method and FFT interpolation method adding cosine window.Then a sweep signal phase difference measurement system is set up using NI virtual instrument technology and Labview graphical programming technology for simulating those algorithms.According to the simulation results,the method of FFT interpolation method adding cosine window can meet the requirements of the fast cycling sweep signal phase difference measurement precision.