CONSTANT PERCENTAGE CLIPPING CIRCUIT

摘要

The input waveform is applied via an input resistor to the inverting input of an operational amplifier. The non-invert-ing input is grounded. In the preferred embodiment, two feedback networks, each comprising a diode and resistor network, are connected between the output and the inverting input of the amplifier. The diodes are oppositely poled. A capacitor is connected to ground at one end and to a charging resistor at the other. The other end of the charging resistor is connected to a junction formed by the resistor and diode in one of the feedback loops. The charging resistor is selected so that the value of the voltage for the reference which is supplied by the voltage across the capacitor C, called ec, is of the value to obtain the percentage clipping desired. A discharge resistor is selected so that the capacitor and discharge resistor have a long time constant with respect to the input frequency of the waveform. The ratio of the resistor in the resistor diode feedback path which supplies the charging current to capacitor C to the resistance of the input resistor provides the constant percentage ratio of the clipper.