Method and apparatus for dynamically inserting gain in an adaptive filter system
AssigneeFreescale Semiconductor, Inc.
InventorsLucio F. C. Pessoa, Roman A. Dyba, Perry P. He, Ahsan Ul Aziz
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Abstract
A method and apparatus for dynamically inserting gain in an adaptive filter is taught. This selective insertion of gain may be used to allow an adaptive filter to converge more quickly and/or to overcome inherent limitations of the adaptive filter. An echo canceller (e.g. 20 and 22 in FIG. 1) is just one possible use for an adaptive filter having a shorter convergence time. However, virtually all uses of an adaptive filter can benefit from a shorter convergence time and/or improved filtering performance.
Claims63
A method for dynamically inserting gain in an adaptive filter system, comprising:
- receiving a desired signal generated by communication system;
- receiving a reference signal;
- filtering the reference signal filtering the reference signal using an adaptive filter to provide an estimated desired signal;
- generating an error signal based on the desired and estimated desired signals;
- and
- applying a predetermined gain function to the error signal during a predetermined period of time to produce an output signal,
- wherein the predetermined period of time for applying the predetermined gain function is independent of the error signal.
A method for detecting an abrupt change in an adaptive filter system, comprising:
- receiving a desired signal generated by a communication system;
- receiving a reference signal;
- filtering the reference signal using an adaptive filter to provide an estimated desired signal;
- generating an error signal based on the desired and estimated desired signals;
- generating an output signal based on the error signal;
- performing power estimations of the desired signal, reference signal, error signal, and estimated desired signal;
- and
- based on the power estimations, detecting an abrupt change of the communication system.
A method for detecting an abrupt change in an adaptive filter system, comprising:
- receiving a desired signal generated by a communication system;
- receiving a reference signal;
- filtering the reference signal using an adaptive filter to provide an estimated desired signal;
- generating an error signal based on the desired and estimated desired signals;
- generating an output signal based on the error signal;
- obtaining a distance between previous coefficients of the adaptive filter and current coefficients of the adaptive filter;
- and
- using the distance to detect an abrupt change of the communication system.
A method for dynamically inserting gain in an adaptive filter system, comprising:
- receiving a desired signal generated by a communication system;
- receiving a reference signal;
- filtering the reference signal using an adaptive filter to provide an estimated desired signal;
- generating an error signal based on the desired and estimated desired signals;
- determining a polynomial function using a power estimation of the error signal and a power estimation of the desired signal;
- generating an adaptive gain function based on the polynomial function and a feedback signal;
- and
- applying the adaptive gain function to the error signal to produce an output signal, wherein the output signal provides the feedback signal.
An adaptive filter system comprising:
- an adaptive filter which receives a reference signal and provides an estimated desired signal;
- and
- a gain unit which receives an error signal based on a desired signal and the estimated desired signal and provides an output signal, the gain unit applying a predetermined gain function to the error signal during a predetermined period of time that is independent of the error signal to produce the output signal.
At least one computer readable medium for storing a plurality of instructions of an adaptive filter system, the plurality of instructions for implementing a method comprising:
- receiving a desired signal and a reference signal;
- filtering the reference signal to provide an estimated desired signal;
- generating an error signal based on the desired and estimated desired signals;
- and
- applying a predetermined gain function to the error signal during a predetermined period of time to produce an output signal,
- wherein the predetermined gain function is independent of the error signal.
Dependencies are inferred from the claim text.