Karl M. Reichard
David C. Swanson
Scott M. Hirsch
Appl. Res. Lab., Penn State Univ., P.O. Box 30, State College, PA 16804
A frequency-domain implementation of the filtered-x algorithm is used to actively control acoustic intensity in a duct. The frequency-domain filtered-x algorithm uses FFT's of the necessary signals to compute the transfer function of the optimal control filter. A version of the algorithm has been adapted to use acoustic intensity, computed from the cross spectrum from two pressure microphones, as the error signal. The results of experiments conducted in a duct are presented which demonstrate the effects of measurement error and control source configuration on controller performance.