Adaptive audio equalizer apparatus and method of determining filter coefficient

An adaptive audio equalizer apparatus comprising:

• an adaptive filter including a finite impulse response filter unit, and a filter coefficient setting unit for determining a filter coefficient for said finite impulse response filter unit, said adaptive filter being for compensating an input signal that is input to said finite impulse response filter unit;
• a target response output unit for providing a target response signal;
• a speaker to which a signal that is output from said adaptive filter is supplied;
• a microphone for detecting an acoustic wave that is output from said speaker and converting it into an electric signal;
• a first calculation unit for calculating a difference between a signal that is output from said microphone and the target response signal, and for providing the result as an error signal;
• a noise signal source for generating a particular noise signal having no correlation to the input signal;
• a finite impulse response filter, in which the same coefficient as in said adaptive filter is set, for compensating the particular noise signal that is input from said noise signal source;
• a multiplying unit for multiplying the output of said finite impulse response filter by a scaling factor;
• and
• a second calculation unit for adding the output of said multiplying unit and said error signal, and for providing the result to said filter coefficient setting unit of said adaptive filter.

A method of determining a filter coefficient in an adaptive audio equalizer apparatus in which a signal that is input via an input terminal is compensated in an adaptive filter and is then supplied to a speaker, and in which a difference between a signal that is output from a microphone and a target response signal serves as an error signal, said method comprising:

• multiplying an output of said adaptive filter by a scaling factor;
• delaying the multiplied signal in a delaying unit;
• adding the delayed signal to said error signal;
• and
• inputting the sum to a filter coefficient setting unit, whereby the output of said adaptive filter is converged to determine said filter coefficient.

A method of determining a filter coefficient in an adaptive audio equalizer apparatus in which a signal that is input via an input terminal is compensated in an adaptive filter and is then supplied to a speaker, and in which a difference between a signal that is output from a microphone and a target response signal serves as an error signal, said method comprising:

• inputting a particular noise signal, having no correlation to the input signal, to a finite impulse response filter in which the same filter coefficient as in said adaptive filter is set;
• multiplying an output of said finite impulse response filter by a scaling factor;
• adding the multiplied signal to said error signal;
• and
• inputting the sum to a filter coefficient setting unit of said adaptive filter;
• whereby the output of said adaptive filter is converged to determine said filter coefficient.