J. Phys. IV France 02 (1992) C1-523-C1-526
DÉTECTION DE FRÉQUENCE ET DE PHASE EN CONTRÔLE ACTIF SYNCHRONEM. de COLIGNY and A. DOUERIN
Laboratoire d'Etudes Aérodynamiques, Bâtiment H, 40 avenue du Recteur Pineau, F-86022 Poitiers cedex, France
Time domain methods for synchronous active control noise need very precise measurement of frequency and phase. In most cases an error detector is put at the place where attenuation is required, and phase detection is achieved by optical or mechanical device. In order to suppress this external mechanical sensor, we use an algorithm calculating the frequency and phase, from main signal given by a pressure sensor or accelerometer. The method is derived from digital phase locked loops, specially using zero-crossing estimation by a least mean square method with specific noise-suppressing filter. Real-time computation is implemented on a TMS 320C25 signal processing system board. Trials demonstrate the reliability of such frequency detection in practical environment with perturbations.
© EDP Sciences 1992