Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
J Acoust Soc Am. 2010 Jul;128(1):EL63-8. doi: 10.1121/1.3453768.
The waveguide invariant is typically defined using of normal modes or ray theory, but it can also be related to the wavenumber-integration method for calculating the acoustic field in a waveguide. In this letter, the Wiener-Khinchin Theorem is used to show that the autocorrelation of the wavenumber-integration kernel, when plotted versus wavenumber difference and frequency, contains striations that can be described by the waveguide invariant.
波导不变量通常使用法向模或射线理论来定义，但也可以与波数积分法相关联，用于计算波导中的声场。在这封信中，使用维纳-辛钦定理证明了当将波数积分核的自相关函数绘制为波数差和频率的函数时，存在可以用波导不变量描述的条纹。
