AUDIO COPY PROTECTION SYSTEM

摘要

An apparatus for applying an anti-copy protection signal for use with switchable head recorders, such as Video Hi-Fi recorders, is described. A high frequency pulsed signal is added to an original signal. The pulses interfere with the compensator circuitry such that the switching of the record head cannot adequately be masked on recording of a signal. On playback, the switching of the recording heads can subsequently be heard. In Video Hi-Fi recorders, the effect of the high frequency signals also interferes with the compressor-expander circuits to worsen the sound of the head switching.