Active control of noise and vibration

摘要: An active system for controlling vibration or sound. The includes a method limiting the output gain G from gradient descent algorithm, such as an LMS according to relationship ##EQU1## and reducing one of first second filter weights W1 W0 that G≦Gmax ensuring canceling signal is never saturated. This eliminates square wave shape which may impart unwanted harmonics resonances dynamic system. In another aspect, drift devices toward saturation when situations are encountered singularities in quadratic performance surface. accomplished by applying leakage factor r(k) function f(k) at near predetermined limit avoid device. can be W(k). Another aspect provide constant, optimum, stable adaptation rate providing optimum coefficient μopt provides uniform, on per period basis all frequencies. Various combinations above described useful control systems.