大功率调制气流声源阵列的相干合成实验研究

完成了调制气流声源阵列的相干合成实验. 提出了利用主动相位控制方法实现调制气流声源阵列相干合成的思路, 介绍了基于随机并行梯度下降算法的声源阵列相干合成的原理. 对利用该算法实现声源阵列的相干合成进行了数值模拟, 完成了双调制气流声源阵列在远场的相干合成实验, 并给出算法参数的合理设置方案. 实验结果显示, 基频成分的相干合成效果明显, 算法收敛时测点处的声压级相比单源发射增加了4 dB, 接近于各单源功率谱中基频成分相干合成、其他频率成分非相干合成的结果; 结果表明实验中算法能够有效控制各调制气流声源辐射声波的相位, 取得了明显的相干合成效果. 关键词： 调制气流声源 相干合成 随机并行梯度下降 高阶谐波

Experimental investigations on coherent combination of high-power and high-intensity air-modulated speakers

In this paper, the experimental investigation of coherently combined air-modulated speakers is achieved. This paper addresses a basic architecture for coherent-combined air-modulated speakers by means of active phase control, and then the fundamental theory for coherent combination using stochastic parallel gradient descent algorithm is described. Numerical simulation on coherently combining sound sources with horn is carried out. Moreover, an experiment of far-field coherently combining two air-modulated speakers has been conducted, and the configuration scheme of parameters in practical terms is presented. Experimental results show that when the algorithm converges, the sound pressure level at the test spot is 4 dB higher than that of single source. A power spectrum analysis indicates that the sound power of coherently combining case is close to the sum of the sound powers between the coherently combining of the fundamental frequency components and the non-coherently combining of the other frequency components for all sound sources. Consequently, it is revealed that the acoustic wave phases for air-modulated speakers can be effectively controlled by the active phase control algorithm, and an evident coherent-combining effect is obtained.
Keywords： air-modulated speaker coherent combination stochastic parallel gradient descent higher harmonics