Abstract: An arrangement is provided for converting an electric signal into an acoustic or a mechanic signal comprising a transducer (11), a linear or nonlinear filter (1) with controllable parameters, a sensor (12), a controller (24), a reference filter (20) and a summer (17). The filter (1) is connected to the electric input of the transducer and is adaptively adjusted to compensate for the linear and/or nonlinear distortions of the transducer and to realize a desired overall transfer characteristic. The filter has for every controllable filter parameter an additional output (7) supplying a gradient signal to the controller and a control input (10). The summer (17) provides an error signal derived from the sensor output and reference filter output. The controller contains a circuit (53) for filtering the gradient signal and/or a circuit (25) for filtering the error signal, a multiplier (51) and an integrator (57) for producing a control signal to update every filter parameter.

Abstract: This invention relates to an arrangement (1) for protecting transducer (3) which converts an electric signal into an acoustic or a mechanic signal against overload and destruction. The arrangement is connected to the electric terminals of the transducer (3) and changes the electric input signal under overload condition. A reference filter (6) connected with the electric input of the transducer provides a monitored signal x(t) related to the load of the transducer (3) to a controller (7). If the amplitude of the monitored signal x(t) exceeds an prescribed threshold value the controller (7) activates a feedback loop realized by the reference filter (6), multiplier (8) and summer (5). This invention provides an effective protection of the transducer with a minimum of elements by using the reference filter (6) as both a signal detector and a controlled attenuation element.

Abstract: This invention relates to an arrangement (14) for protecting a transducer (2) which converts an electric signal into an acoustic or a mechanic signal against overload and destruction. The arrangement is connected to the electric terminals of the transducer and changes the electric input signal under overload condition. This protection arrangement comprises a controller (15), a monitor (16) and an envelope detector (17). The monitor (16) provides a signal indicating the electric or mechanic load of the transducer (2). The peak value of the signal is anticipated by using a predictive filter in the envelope detector (17) or a delay element in the controller (15). If the predicted peak value exceeds an defined limit an attenuation element in the controller (15) is activated and the input signal is changed in time to prevent an overload of the transducer.

Abstract: This invention regards an arrangement to correct the linear and nonlinear transfer behavior of electro-acoustical transducers, consisting of an electro-acoustical transducer, a distortion-reduction network connected to its input terminals, and a support system to fit the distortion-reduction network to the transducer. The distortion-reduction network shows nonlinear transfer characteristics obtained from modelling the transducer and thus changes the electrical signal such that the nonlinear effects of the network compensate for the nonlinear behavior of connected transducer. The result is an overall system with reduced distortion and improved linear transfer behavior. A fitting technique and system is used to change the parameters of the electrical network automatically to fit the actual transfer characteristics of the distortion reduction system to the transducer. Several mechanisms, unique to each transducer, are responsible for generation of nonlinear distortion.