Vehicular active vibratory noise control apparatus
A subtractor subtracts a first control signal output from a first bandpass filter from an error signal, and supplies a differential signal to a second bandpass filter. The second bandpass filter, which has a central frequency of 70 Hz, is affected by an operation of the first bandpass filter, i.e., a first control signal, which has a central frequency of 40 Hz. The first bandpass filter is not affected by an operation of the second bandpass filter, i.e., the second control signal.
1. A vehicular active vibratory noise control apparatus comprising:
a first bandpass filter for extracting a first control signal relative to a first frequency component of a road noise;
a first phase adjuster for generating a first canceling signal by adjusting said first control signal in phase;
a canceling sound output unit for outputting a first canceling sound based on said first canceling signal;
an error signal detector for detecting, as an error signal, a residual vibratory noise due to interference between said first canceling sound and the road noise at an evaluation point;
wherein said first bandpass filter is supplied only with said error signal, which is input thereto, and extracts the first control signal from said error signal;
a second bandpass filter for extracting a second control signal relative to a second frequency component of the road noise;
a second phase adjuster for generating a second canceling signal by adjusting said second control signal in phase; and
an adder for adding said first canceling signal and said second canceling signal together into a sum signal, and outputting the sum signal to said canceling sound output unit;
wherein said canceling sound output unit outputs a canceling sound based on said sum signal;
said error signal detector detects, as said error signal, a residual vibratory noise due to interference between said canceling sound and the road noise; and
said second bandpass filter is supplied with a signal produced by subtracting said first control signal from said error signal, and extracts said second control signal from the supplied signal.
2. A vehicular active vibratory noise control apparatus comprising:
a first phase adjuster for generating a first canceling signal by adjusting a first control signal in phase;
a canceling sound output unit for outputting a first canceling sound based on said first canceling signal;
an error signal detector for detecting, as an error signal, a residual vibratory noise due to interference between said first canceling sound and a road noise at an evaluation point;
a first signal processor for outputting a first control signal;
wherein said first signal processor comprises:
a first standard signal generator for generating a first standard signal relative to a first frequency component of the road noise;
a first adaptive filter for generating said first control signal based on said first standard signal; and
a first filter coefficient updater for sequentially updating a first filter coefficient of said first adaptive filter based on a signal produced by subtracting the first control signal of a preceding sample from the error signal;
a second phase adjuster for generating a second canceling signal by adjusting a second control signal in phase;
an adder for adding said first canceling signal and said second canceling signal together into a sum signal, and outputting the sum signal to said canceling sound output unit; and
a second signal processor for outputting said second control signal;
wherein said canceling sound output unit outputs a canceling sound based on said sum signal;
said error signal detector detects, as said error signal, a residual vibratory noise due to interference between said canceling sound and the road noise; and
said second signal processor comprises:
a second standard signal generator for generating a second standard signal relative to a second frequency component of the road noise;
a second adaptive filter for generating said second control signal based on said second standard signal; and
a second filter coefficient updater for sequentially updating a second filter coefficient of said second adaptive filter, based on a signal produced by subtracting said second control signal of a preceding sample and said first control signal of the preceding sample from said error signal.