中文摘要：

依据一种新型扬声器——声频定向扬声器的基本工作原理，从理论上给出了DSB算法中调制系数对输出信号谐波失真影响的详细推导过程；并指出调制系数越小，失真度越小，但带来的负面效应是小的调制系数将使输出的信号功率相应变小。在此基础上，指DSB算法本身存在一个12dB/倍频程的频率响应倾斜，在设计声频定向扬声器时必须采用算法预处理或换能器频响设计的方法对其进行补偿，以获得较好的声音保真效果。

英文摘要：

The harmonic distortion of the double side band （DSB） algorithm for the audio directional loudspeaker is investigated. The research results show that the harmonic distortion of the DSB algorithm is only influenced by the modulation factor, and is not related to either the modulation signal frequency or the carrier signal frequency. An effective way to obtain a lower harmonic distortion reduce the modulation factor, but it will also result in a lower output signal power. It is necessary and significant for the DSB algorithm to reduce the harmonic distortion and compensate its 12 dB freouencv response slope per octave simultaneously.