用数字方法生成模拟节目信号  

A numerical method for generating simulated programmer signals

作　　者：卢峰[1] 沈勇[1] 陈孝桢[1] 

机构地区：[1]南京大学声学研究所近代声学国家重点实验室,南京210093

出　　处：《声学技术》2003年第4期265-268,共4页Technical Acoustics

摘　　要：在测量扬声器等电声换能器的输入电特性和输入电功率特性时,都要使用模拟节目信号作为测试信号进行功率负荷试验,传统的方法是采用模拟仪器生成的。文章介绍了使用数字方法生成模拟节目信号的技术,利用高斯分布的随机函数产生白噪声序列,经过模拟节目数字滤波器,再通过数字带通滤波器得到所需带宽的噪声序列,最后进行限幅和D/A转换,得到模拟节目信号。问题的难点是模拟节目信号形成滤波器的构造,文章采用频域系统辨识技术,利用共轭梯度法进行搜索,解决了这一问题。利用文章提出的模拟节目信号的数字算法可以方便的生成所需的信号,由此可以利用计算机进行扬声器等电声换能器的功率试验,从而节约了成本,提高了效率。Power test is essential in measuring input electricity characteristics and input power characteristics of electro-acoustic transducers such as loudspeakers, horn loudspeakers, etc. Conventionally, simulated programmer signals for power tests are generated with analog instruments. In this paper, a numerical method for the generation of simulated programmer signals is described. The procedure is to generate a white noise sequence with a random function having a Gaussian distribution, then to filter this sequence through a digital filter for simulated programmer signal-shaping as well as a digital band-pass filter, and finally to chop and D/A convert the resulting sequence into the analog form. The key is to construct the digital filter, which is realized in this work using the method of system identification in the frequency domain and a conjugate gradient descent algorithm. In this way, it is convenient to carry out speaker power tests with a computer.

关 键 词：模拟节目信号 频域系统辨识 电声换能器 数字/模拟转换 共轭梯度法 数字带通滤波器 高斯分布 白噪声 

分 类 号：TN912[电子电信—通信与信息系统]