THE EFFECTS OF SAMPLING RATE AND LENGTH OF AN ADAPTIVE FILTER ON THE ACTIVE CONTROL OF A PLANE SOUND WAVE IN A LOSSY SEMI-INFINITE WAVEGUIDE
✍ Scribed by P. Sergent; D. Duhamel
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 304 KB
- Volume
- 203
- Category
- Article
- ISSN
- 0022-460X
No coin nor oath required. For personal study only.
✦ Synopsis
The active control of a plane sound wave in a semi-infinite waveguide can require a controller with a long weighting function. In a real system constrained to act on-line, the signals are sampled and the weighting function is truncated. Both the sampling rate and the number of coefficients of the adaptive digital filter acting as controller have important effects on active attenuation of noise. The optimal truncated weighting function is therefore determined in order to compare their respective effects. The optimal set-up point of these parameters is then found for a primary excitation consisting of a white noise convolved with an ideal low pass filter. It is shown that the optimal active attenuation depends on two non-dimensional parameters that are composed of four quantities: the speed of the processor, the loss coefficient in the waveguide, the location of the secondary source and the cut-off frequency of the low pass filter.