Basic Research on Active Noise Control for Moving Error Points by Multi-channel Wave Synthesis Method

在嘈杂的房间中，强烈要求采用一些主动噪声控制技术来降低人耳活动时产生的噪声。在这项研究中，我们重点研究了波合成（WS）算法，该算法可以有效地降低周期性噪声，如发动机噪声和风扇噪声，并有望用于移动接收点。得到以下结论：首先，提出了一种新的多通道WS算法，并通过仿真验证了该算法的有效性。其次，利用DSP制作了单通道系统和双通道系统，并通过电路实验证明了它们的降噪性能和收敛性能是足够的。最后，在办公室等实际声场中进行了一些实验，发现该系统总体上是有用的，但在某些声场条件下不稳定。对原因进行了审查，认为建议增加一个扬声器系统来解决这个问题。

It is strongly required to reduce noise at moving persons’ ears in a noisy room by some active noise control techniques. In this research, we focused on the Wave Synthesis (WS) algorithm which is effective for reducing periodic noise such as engine noises and fan tones and is expected to be useful for moving receiving points. The following conclusions were obtained. First, a Multi-Channel WS algorithm was newly deduced and its usefulness was proved by some simulations. Secondary, the single-channel system and the dual channel system were manufactured using DSP, and their noise reducing performance and converging performance were found to be sufficient by some experiments using electrical circuits. Finally, some experiments were performed in real sound fields like an office and the systems were found to be generally useful but to be unstable in some sound field conditions. The reason was examined and an additional speaker systemwas considered to be recommendable to solve this problem.