Signal processing method, apparatus and program

A signal processing apparatus comprising:

• a filter configured to perform filter processing of convoluting a tap coefficient in a first signal sequence to generate a second signal sequence;
• a subtractor configured to subtract the second signal sequence from a third signal sequence including an echo signal of the first signal sequence to generate a fourth signal sequence;
• and
• a correcting unit configured to correct the tap coefficient in accordance with an amount of correction determined using a function of the fourth signal sequence as a parameter,
• wherein the function includes at least one of a first region and a second region, and has values limited, the first region being included in a negative value region of the fourth signal sequence and being a region where the function outputs a value less than a value indicated by a straight line, the second region being included in a positive value region of the fourth signal sequence and being a region where the function outputs a value greater than a value indicated by the straight line, the straight line having a slope and an intercept that are identical to a slope and an intercept of the function assumed when the fourth signal sequence has a value of 0, the slope excluding zero.

A non-transitory computer readable medium encoded with computer executable instructions, wherein the instructions, when executed by a processor, cause the processor to execute a method comprising:

• performing filter processing of convoluting a tap coefficient in a first signal sequence to generate a second signal sequence;
• subtracting the second signal sequence from a third signal sequence including an echo signal of the first signal sequence to generate a fourth signal sequence;
• and
• correcting the tap coefficient in accordance with an amount of correction determined using a function of the fourth signal sequence as a parameter,
• wherein the function includes at least one of a first region and a second region, and has values limited, the first region being included in a negative value region of the fourth signal sequence and being a region where the function outputs a value less than a value indicated by a straight line, the second region being included in a positive value region of the fourth signal sequence and being a region where the function outputs a value greater than a value indicated by the straight line, the straight line having a slope and an intercept that are identical to a slope and an intercept of the function assumed when the fourth signal sequence has a value of 0, the slope excluding zero.