Gordon R T, Vining W D
Chubb & Son Inc., Tulsa, OK 74136-4222.
Am Ind Hyg Assoc J. 1992 Nov;53(11):721-25. doi: 10.1080/15298669291360427.
Active noise control (ANC) is the application of the principle of the superposition of waves to noise attenuation problems. Much progress has been made toward applying ANC to narrow-band, low-frequency noise in confined spaces. During this same period, the application of ANC to broad-band noise or noise in three-dimensional spaces has seen little progress because of the recent quantification of serious physical limitations, most importantly, noncausality, stability, spatial mismatch, and the infinite gain controller requirement. ANC employs superposition to induce destructive interference to affect the attenuation of noise. ANC was believed to utilize the mechanism of phase cancellation to achieve the desired attenuation. However, current literature points to other mechanisms that may be operating in ANC. Categories of ANC are one-dimensional field and duct noise, enclosed spaces and interior noise, noise in three-dimensional spaces, and personal hearing protection. Development of active noise control stems from potential advantages in cost, size, and effectiveness. There are two approaches to ANC. In the first, the original sound is processed and injected back into the sound field in antiphase. The second approach is to synthesize a cancelling waveform. ANC of turbulent flow in pipes and ducts is the largest area in the field. Much work into the actual mechanism involved and the causal versus noncausal aspects of system controllers has been done. Fan and propeller noise can be divided into two categories: noise generated directly as the blade passing tones and noise generated as a result of blade tip turbulence inducing vibration in structures. Three-dimensional spaces present a noise environment where physical limitations are magnified and the infinite gain controller requirement is confronted. Personal hearing protection has been shown to be best suited to the control of periodic, low-frequency noise.
有源噪声控制（ANC）是将波的叠加原理应用于噪声衰减问题。在将有源噪声控制应用于封闭空间中的窄带、低频噪声方面已经取得了很大进展。在同一时期，由于最近对严重物理限制的量化，有源噪声控制在宽带噪声或三维空间噪声中的应用进展甚微，其中最重要的是因果性、稳定性、空间失配和无限增益控制器要求。有源噪声控制利用叠加来产生相消干涉以影响噪声衰减。人们曾认为有源噪声控制利用相位抵消机制来实现所需的衰减。然而，当前的文献指出了有源噪声控制中可能起作用的其他机制。有源噪声控制的类别包括一维场和管道噪声、封闭空间和内部噪声、三维空间中的噪声以及个人听力保护。有源噪声控制的发展源于成本、尺寸和有效性方面的潜在优势。有源噪声控制有两种方法。第一种方法是对原始声音进行处理并以反相形式重新注入声场。第二种方法是合成一个抵消波形。管道和风道中湍流的有源噪声控制是该领域最大的研究方向。已经对其中涉及的实际机制以及系统控制器的因果性与非因果性方面进行了大量研究。风扇和螺旋桨噪声可分为两类：直接作为叶片通过频率产生的噪声以及由于叶片尖端湍流引起结构振动而产生的噪声。三维空间呈现出一种噪声环境，其中物理限制被放大，并且面临无限增益控制器要求。个人听力保护已被证明最适合控制周期性的低频噪声。
