Declercq Nico F, Degrieck Joris, Leroy Oswald
Soete Laboratory, Department of Mechanical Construction and Production, Ghent University, Sint Pietersnieuwstraat 41, B-9000 Ghent, Belgium.
Ultrasonics. 2005 Oct;43(9):764-8. doi: 10.1016/j.ultras.2005.04.002.
In electronics, it is well known that filtering devices can be made that are able to decompose a signal instantaneously into a number of real frequency components. This procedure is equivalent to a numerical real time Fourier transform. However, it is also known that an electronic signal can be decomposed not just in real frequency components, but also in complex frequency components. The current paper shows that it is theoretically possible to create a device, made of a periodically rough surface and a system that transforms the electronic signal into acoustic waves, that can be used to measure the amplitude attributed to considered complex frequency components of an electronic signal, in real time. This 'thought device' is mainly based on the directivity of diffracted sound and the complex frequency dependence of this directivity.
在电子学领域，众所周知，可以制造出能够瞬间将信号分解为多个实频率分量的滤波装置。这一过程等同于数值实时傅里叶变换。然而，同样众所周知的是，电子信号不仅可以分解为实频率分量，还可以分解为复频率分量。本文表明，理论上有可能制造出一种由周期性粗糙表面和将电子信号转换为声波的系统组成的装置，该装置可用于实时测量电子信号中特定复频率分量的幅度。这种“概念装置”主要基于衍射声的方向性以及该方向性对复频率的依赖性。
