Patent ID: 8098837
Filing Date: 2012-01-17
Classification: G10K

Abstract:
1. An active noise control apparatus comprising: a controller for generating a first control signal for canceling out a noise in a passenger compartment of a vehicle; a sound output unit for outputting a canceling sound for canceling out said noise based on said first control signal into said passenger compartment; and a canceling error signal detecting unit for outputting a canceling error signal representing a canceling error sound between said noise and said canceling sound to said controller; wherein said controller comprises: an A/D converter for converting said canceling error signal from an analog signal into a digital signal; an echo canceler for correcting said first control signal into a digital echo canceling signal based on a corrective value corresponding to transfer characteristics between said sound output unit and said canceling error signal detecting unit; a subtractor for generating a first basic signal by subtracting said digital echo canceling signal from the digital canceling error signal; a delay filter for generating a second basic signal by delaying said first basic signal by a time corresponding to a ¼ period of a resonant frequency determined by resonant characteristics of said passenger compartment; a first adder for combining said first basic signal and said second basic signal into said first control signal; a basic signal generating unit for generating a third basic signal having a predetermined control frequency based on the frequency of a vibratory noise generated by a vibratory noise source mounted on said vehicle; a reference signal generating unit for generating a reference signal by correcting said third basic signal based on said corrective value; an adaptive filter for generating a second control signal for canceling out said noise based on said third basic signal; a filter coefficient updating unit for successively updating a filter coefficient of said adaptive filter in order to minimize said first basic signal based on said first basic signal and said reference signal; a second adder for adding said first control signal and said second control signal into a third control signal; and a D/A converter for converting said third control signal from a digital signal into an analog signal and outputting the analog third control signal to said sound output unit; wherein said sound output unit outputs said canceling sound based on said third control signal into said passenger compartment.