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58results about How to "Good echo cancellation" patented technology

Adaptive echo cancellation method adopting memory proportionate affine projection and based on M-estimation

The invention discloses an adaptive echo cancellation method adopting memory proportionate affine projection and based on M-estimation. The adaptive echo cancellation method comprises the following steps: A, a remote signal is sampled; B, in echo estimation, a filter input vector X(n) passes through an adaptive filter and an output value y(n), namely an echo estimation value y(n), is obtained and equal to XT(n)w(n); C, in echo cancellation, a near-end signal d(n) with the echo, acquired by a near-end microphone and the output value y(n) of the adaptive filter are subjected to subtraction operation, and a return signal, namely a residual signal e(n), is returned to a far end and equal to d(n)-y(n); D, in updating of a tap weight vector of the filter, the method adopting memory proportionate affine projection and based on M-estimation is used and the tap weight vector w(n+1) of the adaptive filter at next moment n+1 is calculated and equal to w(n)+mu P(n)(UT(n)P(n)+delta IK)-1 psi [E(n)]; E, n is set to be n+1, and the steps B, C and D are repeated until a call is ended. The method has a good cancellation effect on an acoustic echo of a communication system and is high in convergence speed and small in steady-state error.
Owner:SOUTHWEST JIAOTONG UNIV

Low complexity phone echo self-adaption eliminating method

The invention discloses a low complexity phone echo self-adaption eliminating method. The method mainly comprises the steps of: A, far-end signal filtration: obtaining a large-step filtering value y1(n) and a small-step filtering value y2(n); B, convex combination: completing the convex combination of the large-step filtering value y1(n) and the small-step filtering value y2(n) so as to obtain a combined filtering value y(n), wherein y(n)=lambda(n)y1(n)+(1-lambda(n))y2(n); C, echo cancellation: completing the subtraction of a near-end signal d(n) which has echo and is picked by a near-end microphone and the combined filtering value y(n), and then sending the signal back to a far end, wherein a return signal is a total residual signal e(n), and e(n)=d(n)-y(n); D, updating the weight coefficient of filtering device taps; E, updating the weight of the filtering device, i.e. updating a hybrid parameter a(n) through a formula which is simplified by a sign function; F, defining the weight of the filtering device; and G, setting n=n+1, and repeating the steps of A, B, C, D, E and F until the conversation is over. The method has strong identification capability to sparse telephone communication systems, and particularly has quick convergence rate and small steady state error in a transition period; an echo eliminating effect is good; and moreover, the method is low in calculation complexity, low in hardware cost and easy to implement.
Owner:SOUTHWEST JIAOTONG UNIV

Improved convex combination decorrelation proportionate self-adaption echo cancellation method

An improved convex combination decorrelation proportionate self-adaption echo cancellation method comprises the steps that first, far-end signal filtering is carried out, the input vector X(n) of a convex combination self-adaption echo cancellation filter is formed by the discrete value of a far-end signal, and after filtering is carried out on the input vector, a large-step-length filtering value y1(n) and a small-step-length filtering value y2(n) are obtained; second, decorrelation operation is carried out on the input vector X(n), the result of decorrelation operation serves as the weight coefficient updating direction vector Z(n) of the convex combination self-adaption echo cancellation filter; third, convex combination is carried out, the large-step-length filtering value y1(n) and the small-step-length filtering value y2(n) are subjected to convex combination through weight lambda (n), and a combination filter value y(n) is obtained; fourth, echo cancellation is carried out, the combination filter value y(n) is subtracted from a near-end signal d(n) with an echo, and the subtracted near-end signal d(n) is fed back to the far end; fifth, a filter tap weight coefficient is updated; sixth, the weight of the filter is updated; seventh, the weight of the filter is limited; eighth, n is made to be equal to n+1, the first step to the seventh step are repeated till a conversation is over. According to the method, a high rate of convergence can be obtained, the steady state error can be small, and a good anti-jamming capability is achieved.
Owner:SOUTHWEST JIAOTONG UNIV

Exponential function echo cancellation method based on one-norm and zero-attractor

The invention relates to an exponential function echo cancellation method based on one-norm and zero-attractor, and discloses a zero-norm sub-band echo cancellation method. The method comprises the following steps: A, remote signal sampling; B, echo signal estimation; C, echo signal cancellation; D, filter tap weight coefficient updating; and E, assuming that n is equal to n+1, and repeating steps B, C and D to achieve real-time echo cancellation. According to the method disclosed by the invention, a one-norm of a weight coefficient vector is adopted in the derivation of a weight coefficient vector updating formula, the norm relates to FORMULA, wherein gamma is a proportion parameter of the one-norm of the weight coefficient vector, zero-attractor Rho (n) is obtained from the derivation, Rho (n) is equal to b.sgnW(n), which means that the speed that the weight coefficient vector is updated to zero is faster under sparse systems; a method for taking an exponential function as a cost function is adopted during weight update, and thus the cost function is changed to FORMULA when updating the weight coefficient vector, and a new step length factor is introduced to ensure that output signals of a filter can obtain faster convergence and lower steady state maladjustment under Gaussian signals and the sparse systems.
Owner:SOUTHWEST JIAOTONG UNIV

Convex combination adaptive echo cancellation method for affine projection sign subband adaptive filter

The invention discloses a convex combination adaptive echo cancellation method for an affine projection sign subband adaptive filter. The method mainly comprises the following steps: A, far-end signal filtering: performing far-end signal filtering to obtain the output vector Y1(n) of a large-step-length filter and the output vector Y2(n) of a small-step-length filter; B, convex combination: performing convex combination on the output vector Y1(n) and the output vector Y2(n) of the large-step-length filter and the small-step-length filter to obtain a combination filtering value Y(n) (Y(n)= lambda(n)Y1(n)+(1-lambda(n))Y2(n)), and performing convex combination on the tap weight vector W1(n) of the large-step-length filter and the tap weight vector W2(n) of the small-step-length filter to obtain a total filter group tap weight vector W(n) (W(n)=lambda(n)W1(n)+(1-lambda(n))W2(n); C, echo cancellation: subtracting the combination filter value Y(n) from an echo-carrying affine projection near-end signal D(n) picked up by a near-end microphone to obtain a net signal E(n) (E(n)=D(n)-Y(n)), and transmitting the net signal back to a far end; D, updating the tap weight coefficients of the filters; E, weight update of the filters: updating hybrid parameters a(n); and F, iteration: repeating the steps above under the condition that n=n+1 till the end of a conversation. The method has the advantages of high cancellation capability on the acoustic echo of a sparse communication system, high convergence speed, small steady-state error and good echo cancellation effect.
Owner:SOUTHWEST JIAOTONG UNIV

Minimum mean cubic absolute value echo elimination method of convex combination

The invention discloses a minimum mean cubic absolute value echo elimination method of convex combination. The method comprises the following steps: A, performing far-end signal filtering to obtain alarge step length filtering value y1(n) and a small step length filtering value y2(n); B, performing convex combination: performing convex combination on the large step length filtering value y1(n) and the small step length filtering value y2(n) to obtain a combined filtering value y(n); C, performing echo cancellation; D, performing filter tap weight coefficient update: respectively performing tap weight coefficient update of each of a large step length filter and a small step length filter based on the minimum mean cubic absolute value algorithm; E, performing weight update of the filter; F,performing weight limitation of the filter; G, enabling n=n+1, repeating the steps A, B, C, D, E and F until the call is ended. The cost function for the tap weight coefficient update of each of thesmall and large filters is the mean cubic absolute value of the total residual signal e(n), the error is amplified, the operational precision is high; through the fast convergence of the large step length filter and the small steady state error of the small step length filter, and the steady state error is small, the convergence speed is fast, and the echo cancellation effect is good.
Owner:SOUTHWEST JIAOTONG UNIV

Zero-norm set membership affine projection adaptive echo cancellation method based on weight vector reuse

A zero-norm set membership affine projection adaptive echo cancellation method based on weight vector reuse comprises the following steps: A, remote signal sampling; B echo estimation: obtaining an output value y(n) at a current time n through an adaptive filter based on an input vector X(n) of the adaptive filter at the current time n, wherein y(n) is the estimated value of echo, and y(n)=X<T>(n)*w(n); C, echo cancellation: subtracting the output value y(n) of the adaptive filter at the current time n from a near-end signal d(n) with echo at the current time n picked up by a near-end microphone to get a residual signal e(n), wherein e(n)=d(n)-y(n), and transmitting the residual signal back to a remote end; D, filter tap weight vector updating: getting a tap weight vector w(n+1) (Please see the description for the expression) of the filter at next time n+1 using a zero-norm set membership affine projection method based on weight vector reuse; and E, letting n=n+1, and repeating the steps B, C and D until the end of the call. The method has the advantages of good cancellation effect for acoustic echo of a communication system, high convergence rate, and small steady-state error.
Owner:聊城来通国际贸易有限公司

A set-member adaptive echo cancellation method based on correlation entropy induction

An adaptive echo cancellation method based on correlation entropy is disclosed. The method comprises the following steps: A, collecting far-end signals, sampling far-end signals transmitted from far-end to obtain the discrete value x (n) of far-end input signals at the current time n, and the filter input signal vector is x (n) = [x (n), x (n-1),..., x (n-L+1)] T; B, sampling far-end signals transmitted from far-end to obtain the discrete value x (n) of far-end input signals at the current time n. B, estimate an echo signal, passing an input signal vector x (n) of that current time n through an adaptive filt, and outputting a value y (n) thereof, that is, an estimated value of the echo signal; C, canceling the echo, sampling with a near-end microphone to obtain the near-end signal d (n) ofthe current time n of the echo return, subtracting the estimated value y (n) of the echo signal; D, updating the tap weight coefficients of the filter, and calculating a tap weight vector w (n+1), w(n+1) = w (n) + Mu(n) U (n) (UT (n) U (n)) of n+1 at the next time of the filter; 1E(n)-C (n); E, let n=n+1, repeating the process of A, B, C, D, E until the end of the call. This method can obtain faster convergence rate and lower steady-state error, and the echo cancellation effect is good.
Owner:SOUTHWEST JIAOTONG UNIV

Self-adaptive echo cancellation method based on time-varying parameters

The invention discloses a self-adaptive echo cancellation method based on time-varying parameters. The adaptive echo cancellation method comprises the following steps: A, far-end signal sampling; B, echo signal estimation: obtaining an output value y (n) from the filter input vector X (n) through an seld-adaptive filter, namely, an echo estimation value y (n), y (n) = WT (n) X (n); C, echo signalelimination: subtracting the near-end signal d (n) with echo picked up by the near-end microphone from the output value y (n) of the self-adaptive filter, and sending the subtracted near-end signal d(n) and the subtracted output value y (n) back to the far end, the returned signal being a residual signal e (n), and e (n) = d (n)-; y (n); D, updating a tap weight vector of the filter; estimating aresidual signal square sequence Ae (n) in the window according to the current moment n, obtaining a smooth square value of the residual signal, further obtaining an adjusting parameter (n) of a time-varying proportional control factor and a time-varying proportional control factor gk (n), and finally obtaining an adaptive filter tap weight W (n + 1) at the next moment; and E, enabling n to be equal to n + 1, and repeating the steps A, B, C and D until the conversation is finished. The method has the advantages of good elimination effect on acoustic echoes of a communication system, high convergence speed and small steady-state error.
Owner:SOUTHWEST JIAOTONG UNIV

Normalized sub-band adaptive echo elimination method based on M estimation

The invention relates to a normalized sub-band adaptive echo elimination method based on M estimation. The method comprises steps that A, a sub-band signal is acquired; B, adaptive filtering, an mth filter output value ym(k) at the sampling time n=kM is acquired through an adaptive filter on the basis of an mth adaptive filter input vector Xm(k) at the sampling time n=kM, and an equation described as the specification is acquired; C, echo cancellation, a kth time segment extraction value d<->m(k) of an mth near-end sub-band signal subtracts the mth filter output value ym(k) at the sampling time n=kM to acquire an mth sub-band residual error em(k) at the sampling time n=kM, and an equation described as the specification is acquired; D, a filter tap weight vector is updated, a normalized sub-band method based on M estimation is utilized, a tap weight vector w(k+1) of the adaptive filter at the time n=(k+1)M is acquired, and an equation described as the specification is acquired; and E, k=k+1 is made, the steps of B, C and D are repeated till conversation is over. Through the method, the acoustic echo elimination effect for a communication system is good, a convergence speed is fast, and a stable state error is small.
Owner:杭州东南吉通网络有限公司

Proportional affine projection echocancellation method of convex combination coefficient differences

The invention discloses a proportional affine projection echocancellation method of convex combination coefficient differences. The method includes the following steps: A. far-end signals sampling and filtering, A1. a far-end dispersion input signal constitutes an input vector X (n) of a convex combination adaptive filtering echocancellation filter; A2. inputting a filter to the vector X (n) to obtain filtering values y1 (n) and y2 (n) of a large step length and a small step length; B. echo offsetting, subtracting a near-end signal d (n) and a combination filter output value y (n) to obtain a total residual signal e (n) after echocancellation, and transmitting the total residual signal e (n) to a far end; C. conducting convex combination, conducting convex combination on the output value y1 (n) and y2 (n) of the large step length and the small step length through a weight [lambda] to obtain a combination output value y (n), and conducting convex combination on tap weight coefficients W1 (n) and W2 (n) through the weight [lambda] to obtain a tap weight coefficient W (n) of a tap filter; D. updating a tap weight vector of a filter; E. updating the weight of the filter; F. limiting the weight of the filter; G. repeating the steps of A, B, C, D, E, F, thus realizing echocancellation. The method has strong identification capability, rapid convergence, strong tracking capability, low stability error rate, and excellent effects of echocancellation.
Owner:SOUTHWEST JIAOTONG UNIV

A Low Complexity Adaptive Cancellation Method for Telephone Echo

The invention discloses a low complexity phone echo self-adaption eliminating method. The method mainly comprises the steps of: A, far-end signal filtration: obtaining a large-step filtering value y1(n) and a small-step filtering value y2(n); B, convex combination: completing the convex combination of the large-step filtering value y1(n) and the small-step filtering value y2(n) so as to obtain a combined filtering value y(n), wherein y(n)=lambda(n)y1(n)+(1-lambda(n))y2(n); C, echo cancellation: completing the subtraction of a near-end signal d(n) which has echo and is picked by a near-end microphone and the combined filtering value y(n), and then sending the signal back to a far end, wherein a return signal is a total residual signal e(n), and e(n)=d(n)-y(n); D, updating the weight coefficient of filtering device taps; E, updating the weight of the filtering device, i.e. updating a hybrid parameter a(n) through a formula which is simplified by a sign function; F, defining the weight of the filtering device; and G, setting n=n+1, and repeating the steps of A, B, C, D, E and F until the conversation is over. The method has strong identification capability to sparse telephone communication systems, and particularly has quick convergence rate and small steady state error in a transition period; an echo eliminating effect is good; and moreover, the method is low in calculation complexity, low in hardware cost and easy to implement.
Owner:SOUTHWEST JIAOTONG UNIV

An Improved Convex Combination Decorrelation Proportional Adaptive Echo Cancellation Method

An improved convex combination decorrelation proportionate self-adaption echo cancellation method comprises the steps that first, far-end signal filtering is carried out, the input vector X(n) of a convex combination self-adaption echo cancellation filter is formed by the discrete value of a far-end signal, and after filtering is carried out on the input vector, a large-step-length filtering value y1(n) and a small-step-length filtering value y2(n) are obtained; second, decorrelation operation is carried out on the input vector X(n), the result of decorrelation operation serves as the weight coefficient updating direction vector Z(n) of the convex combination self-adaption echo cancellation filter; third, convex combination is carried out, the large-step-length filtering value y1(n) and the small-step-length filtering value y2(n) are subjected to convex combination through weight lambda (n), and a combination filter value y(n) is obtained; fourth, echo cancellation is carried out, the combination filter value y(n) is subtracted from a near-end signal d(n) with an echo, and the subtracted near-end signal d(n) is fed back to the far end; fifth, a filter tap weight coefficient is updated; sixth, the weight of the filter is updated; seventh, the weight of the filter is limited; eighth, n is made to be equal to n+1, the first step to the seventh step are repeated till a conversation is over. According to the method, a high rate of convergence can be obtained, the steady state error can be small, and a good anti-jamming capability is achieved.
Owner:SOUTHWEST JIAOTONG UNIV
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