WAVEFORM CLIPPING CIRCUITS

摘要

WAVEFORM CLIPPING CIRCUITS A soft clipping circuit for a telephone subset limits the output signal amplitude to the line thus preventing output stage saturation with consequent reduction in impedance. The circuit includes a variable gain input stage (I/P), a main speech signal amplifier (AMP1) and a rectifying amplifier feed back stage (AMP2) that generates a control current whenever the output speech signal exceeds a predetermined threshold. This current is fed to the input stage so as to reduce its gain. Typically the input stage comprises a long tailed transistor pair amplifier, the control current being fed to the tail of the pair.