When impedance elements such as FETs are used in attenuators, the elements have linear responses only when the signals attenuated are below certain signal levels. When signal conditions causing the element to operate non-linearly are detected, bootstrapping is applied to reduce the voltage across the element so that the element will operate linearly. The control signal at the gate of the element is then modified to compensate for the increase in effective impedance of the element caused by bootstrapping. The improved attentuators are especially useful in signal compressors and expanders.
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part application of Ser. No. 06/835,245, filed Mar. 3, 1986, entitled "Attenuator Circuit Employing Bootstrapping", and now abandoned.
An audio system having a main chassis including an audio preamplifier and a remote chassis including a power amplifier has a clipping level detector circuit in the remote chassis for detecting the onset of clipping by the power amplifier and has a gain control element in the main chassis for controlling the gain of the preamplifier. Thus, clipping distortion is eliminated without introduction of other distortion and while preserving the spectral balance of the audio signal.
