The audio characteristics and measuring methods of digital audio equipment such as compact disc player and digital audio amplifier are introduced. When testing a digital audio equipment, how to select and setup band-pass filter, low-pass filter and fs / 2 band-pass filter are discussed in detail. 介绍了激光唱机和数字功率放大器等数字音频产品的音频特性及其测量方法,并详细讨论了在测试过程中如何选取和设置带通滤波器、低通滤波器和fs/2带通滤波器。