Circuit and method for controlling an audio system

摘要

A circuit for directly differentiating stereo and mono signals regardless of whether a pilot carrier signal is present. The circuit generally includes a detection circuit coupled to a control circuit. The detection circuit subtracts the left and right audio signals, and the control circuit compares the resulting difference to a reference signal. When the reference signal exceeds the difference between the left and right signals, the control circuit judges that the inputs are mono. The circuit is advantageously used to automatically disable a repercussion function of a stereo system when a mono signal is received.