Circuit/System Description

The active noise cancellation system uses four microphones in the vehicle headliner: one above each front seating position, and two above the rear seats. The Audio Amplifier/Active Noise Cancellation Module provides a bias voltage to each microphone (+) and (-) signal circuits for operation of the microphone. The microphones monitor the vehicle cabin for undesirable engine sounds. The Audio Amplifier uses the microphone inputs and an engine RPM signal to determine the frequency of the undesirable sound.