设计数字相移器的一种新方法  

A Novel Approach for Designing Digital Phase Shifter

作　　者：张燕武[1] 马远良[1] 

机构地区：[1]西北工业大学

出　　处：《西北工业大学学报》1993年第3期320-324,共5页Journal of Northwestern Polytechnical University

摘　　要：在声纳或雷达波束形成、多通道信号传输的相位校正、数字通讯中的调制解调器设计等场合,都需要获得窄带恒定相移.本文给出了数字相移器设计的一种新方法,其原理以自适应建模为基础.这种方法可以方便地在信号处理机中实现.还给出了几个设计实例.Narrow-band constant phase shift is needed in various cases including MODEM design in digital communications, phase correction for multi-channel signal transmission and beamforming of sonar or radar. This paper presents a novel approach for designing a digital phase shifter[8]; no such approaches were mentioned by D.C.M. Horvat et al[4] as late as in 1992. The underlying principle is adaptive modeling[7]. A signal source composed of N sinusoids serves as the input of both a pseudo-filter (describing the design requirement) and an adaptive FIR filter. The LMS algorithm is chosen to adjust the adaptive filter, making the output of the adaptive FIR filter approach that of the pseudo-filter. After the adaptive filter converges, a set of stable-state weights is obtained. A FIR filter with these weights as its unit-sample response is the phase shifter we need. Designed with this method, a FIR filter with only 4 taps can implement arbitrary constant phase shift within normalized bandwidth of 0.04. Compared with existing methods[1,2,3,4], a phase shifter designed with this new approach is effective and simple. With light computation load, phase shift can be conveniently implemented in real time. If wider bandwidth or higher precision is required, this approach still works, provided that some design parameters should be adjusted correspondingly. This approach has been applied to a sonar phase-shift beamformer with TMS320C25 as CPU. The emulation result[8] is fairly satisfactory. Thus it is indicated that this novel approach performs well.

关 键 词：数字相移器 数字信息处理 数字通信 

分 类 号：TN911.72[电子电信—通信与信息系统]