Method and apparatus for controlling coefficients of adaptive filter

Claim 3

A method as defined in claim 1, also comprising: obtaining information relating to a short-time average magnitude and a long-time average magnitude of the coefficients of said adaptive filter and utilizing said information to obtain a ratio between said short-time average magnitude and said long-time average magnitude; wherein said step of adaptively varying corrections applied to the coefficients of said adaptive filter includes the step of adaptively varying the amount of the corrections applied to the coefficients of said adaptive filter according to the ratio between the short-time average magnitude and the long-time average magnitude of the coefficients of said adaptive filter.

Claim 6

A method as defined in claim 3, also comprising: obtaining information relating to a short-time average magnitude and a long-time average magnitude of the coefficients of said adaptive filter and utilizing said information to obtain a ratio between said short-time average magnitude and said long-time average magnitude; wherein said step of adaptively varying corrections applied to the coefficients of said adaptive filler includes the step of adaptively varying the amount of the corrections applied to the coefficients of said adaptive filter according to the ratio between the short-time average magnitude and the long-time average magnitude of the information on the magnitude of the output signal.

Claim 7

A method as defined in claim 4, wherein said step of utilizing said information to obtain the ratio between the short time average magnitude and long time average magnitude comprises the steps of inverting the long time average magnitude to obtain an inverted signal and multiplying the inverted signal by the short time average magnitude, wherein the step of inverting is made by a linear approximation of an exponent of 2.

Claim 8

A method as defined in claim 5, wherein the step of inverting includes the step of determining a variable X according to a linear approximation of -2 -2-r X+2 -r-1 (2 -1 +1) using the maximum integer r not exceeding log 2 (x).

Claim 9

Electronic filter apparatus comprising: an adaptive filter which upon receiving a reference signal generates a pseudo output for an unknown system; first means for generating a mixed signal from interference signals and an output signal of the unknown system; a first subtracter for subtracting the pseudo output from said mixed signal; an information extraction circuit that receives coefficients for the adaptive filter to extract the information on the magnitude of said coefficients and generate an output (a); an arithmetic circuit to receive the output (a) for calculating and providing a signal (b) which decreases as the output (a) increases or increases as the output (a) decreases; second means for correcting the coefficients of the adaptive filter utilizing the outputs from the first subtracter, said arithmetic circuit and the reference signal; and said information extraction circuit comprising a square circuit for developing the output of said adaptive filter.

Claim 10

Electronic filter apparatus comprising: an adaptive filter which upon receiving a reference signal generates a pseudo output for an unknown system; first means for generating a mixed signal from interference signals and an output signal of the unknown system; a first subtracter for subtracting the pseudo output from said mixed signal; an information extraction circuit that receives coefficients for the adaptive filter to extract the information on the magnitude of said coefficients and generate an output (a); an arithmetic circuit to receive the output (a) for calculating and providing a signal (b) which decreases as the output (a) increases or increases as the output (a) decreases; second means for correcting the coefficients of the adaptive filter utilizing the outputs from the first subtracter, said arithmetic circuit and the reference signal; and said information extraction circuit comprising a square circuit for developing the output of said adaptive filter.

Claim 11

Electronic filter apparatus as set forth in claim 7, wherein said arithmetic circuit comprises a first average circuit for averaging an input signal with a first parameter, a second average circuit for averaging the input signal with a second parameter that differs from the first parameter in said first average circuit, and a divider for developing a ratio of an output of said first average circuit and an output of said second average circuit.

Claim 12

Electronic filter apparatus as in claim 8 wherein said divider comprises an inverter for outputting an inverted signal of the output from said second average circuit and a first multiplier for multiplying the inverted signal with the output from said first average circuit.

Claim 13

Electronic filter apparatus as set forth in claim 7 wherein said information extraction circuit comprises additional square circuits which together with said square circuit form a group of square circuits each developing a squared value of each coefficient value; and a summer for developing a summed value of outputs of said group of square circuits.

Claim 14

Electronic filter apparatus as in claim 7 wherein said arithmetic circuit is an inverse circuit comprising: an amplitude evaluation circuit to provide the maximum integer r not exceeding log 2 (X) of an input signal X; a second multiplier to multiply the output of said amplitude evaluation circuit by -1; a second adder to add -1 to the out/put of said second multiplier; a third adder to provide the sum of the outputs of said second multiplier and said second adder; a first address generation circuit to provide a RAM address signal to give an exponent of 2 corresponding to the output of said third adder; a second address generation circuit to provide a RAM address signal to give an exponent of 2 corresponding to the output of said second adder; a RAM to provide a corresponding exponent output of 2 on receiving the outputs of said first and second address generation circuits; a third multiplier to multiply the output corresponding to the address generated from said first address generation circuit in said RAM by -1; a fourth multiplier to multiply the output of said third multiplier by the input signal to the input terminal; a fifth multiplier to multiply the output corresponding to the address generated by said second address generation circuit in said RAM by 1.5; and a fourth adder to add the outputs of said fifth and fourth multipliers for outputting from the output terminal.

Claim 15

Electronic filter apparatus comprising: an adaptive filter which upon receiving a reference signal generates a pseudo output for an unknown system; first means for generating a mixed signal from interference signals and an output signal of the unknown system; a first subtracter for subtracting the pseudo output from said mixed signal; an information extraction circuit comprising a circuit that receives coefficients for the adaptive filter to extract the information on the magnitude of said coefficients and generate an output (a); an arithmetic circuit to receive the output (a) for calculating and providing a signal (b) which decreases as the output (a) increases or increases as the output (a) decreases; second means for correcting the coefficients of the adaptive filter utilizing the outputs from the first subtracter, said arithmetic circuit and the reference signal; and said information extraction circuit also comprising an absolute value circuit for developing an absolute value of the output of said adaptive filter.

Claim 16

Electronic filter apparatus comprising: an adaptive filter which upon receiving a reference signal generates a pseudo output for an unknown system; first means for generating a mixed signal from interference signals and an output signal of the unknown system; a first subtracter for subtracting the pseudo output from said mixed signal; an information extraction circuit comprising a circuit that receives coefficients for the adaptive filter to extract the information on the magnitude of said coefficients and generate an output (a); an arithmetic circuit to receive the output (a) for calculating and providing a signal (b) which decreases as the output (a) increases or increases as the output (a) decreases; second means for correcting the coefficients of the adaptive filter utilizing the outputs from the first subtracter, said arithmetic circuit and the reference signal; and said information extraction circuit also comprising an absolute value circuit for developing an absolute value of the output of said adaptive filter.

Claim 17

Electronic filter apparatus as set forth in claim 12 wherein said information extraction circuit further comprises additional absolute value circuits which together with other portions of said information extraction circuit form a group of absolute value circuits each developing an absolute value of each coefficient value, and a first summer for developing a summed value of the outputs of said group of absolute value circuits.

Claim 18

Electronic filter apparatus comprising: an adaptive filter which upon receiving a reference signal generates a pseudo output for an unknown system; first means for generating a mixed signal from interference signals and an output signal of the unknown system; a first subtracter for subtracting the pseudo output from said mixed signal; an information extraction circuit that receives the output signal for the adaptive filter to extract the information on the magnitude of coefficients for the adaptive filter and generate an output (a); an arithmetic circuit to receive the output (a) for calculating and providing a signal (b) which decreases as the output (a) increases or increases as the output (a) decreases; second means for correcting the coefficients of the adaptive filter utilizing the outputs from the first subtracter, said arithmetic circuit and the reference signal; and said information extraction circuit comprising a square circuit for developing the output of said adaptive filter.

Claim 19

Electronic filter apparatus comprising: an adaptive filter which upon receiving a reference signal generates a pseudo output for an unknown system; first means for generating a mixed signal from interference signals and an output signal of the unknown system; a first subtracter for subtracting the pseudo output from said mixed signal; an information extraction circuit that receives the output signal for the adaptive filter to extract the information on the magnitude of coefficients for the adaptive filter and generate an output (a); an arithmetic circuit to receive the output (a) for calculating and providing a signal (b) which decreases as the output (a) increases or increases as the output (a) decreases; second means for correcting the coefficients of the adaptive filter utilizing the outputs from the first subtracter, said arithmetic circuit and the reference signal; and said information extraction circuit comprising a square circuit for developing the output of said adaptive filter.

Claim 20

Electronic filter apparatus comprising: an adaptive filter which upon receiving a reference signal generates a pseudo output for an unknown system; first means for generating a mixed signal from interference signals and an output signal of the unknown system; a first subtracter for subtracting the pseudo output from said mixed signal; an information extraction circuit that receives the output signal of the adaptive filter to extract the information on the magnitude of coefficients for the adaptive filter and generate an output (a); an arithmetic circuit to receive the output (a) for calculating and providing a signal (b) which decreases as the output (a) increases or increases as the output (a) decreases; second means for correcting the coefficients of the adaptive filter utilizing the outputs from the first subtracter, said arithmetic circuit and the reference signal; and said information extraction circuit comprising an absolute value circuit for developing an absolute value of the output of said adaptive filter.

Claim 21

Electronic filter apparatus comprising: an adaptive filter which upon receiving a reference signal generates a pseudo output for an unknown system; first means for generating a mixed signal from interference signals and an output signal of the unknown system; a first subtracter for subtracting the pseudo output from said mixed signal; an information extraction circuit that receives the output signal of the adaptive filter to extract the information on the magnitude of coefficients for the adaptive filter and generate an output (a); an arithmetic circuit to receive the output (a) for calculating and providing a signal (b) which decreases as the output (a) increases or increases as the output (a) decreases; second means for correcting the coefficients of the adaptive filter utilizing the outputs from the first subtracter, said arithmetic circuit and the reference signal; and said information extraction circuit comprising an absolute value circuit for developing an absolute value of the output of said adaptive filter.

Claim 22

Electronic filter apparatus as set forth in claim 5, wherein said arithmetic circuit comprises a first average circuit for averaging an input signal with a first parameter, a second average circuit for averaging the input signal with a second parameter that differs from the first parameter in said first average circuit, and a divider for developing a ratio of an output of said first average circuit and an output of said second average circuit.

Claim 23

Electronic filter apparatus as in claim 15 wherein: said arithmetic circuit comprises a first average circuit for averaging an input signal with a first parameter, a second average circuit for averaging the input signal with a second parameter that differs from the first parameter in said first average circuit, and a divider for developing a ratio of an output of said first average circuit and an output of second average circuit; and said divider comprises an inverter for outputting an inverted signal of the output from said second average circuit and a first multiplier for multiplying the inverted signal with the output from said first average circuit.