DTMF signal detection/removal using adaptive filters

Details DTMF signal detection/removal using adaptive filters DTMF signal detection/removal using adaptive filters

1997-01-31

1999-03-30

Hunter, Daniel S.

Telephonic communications

Supervisory or control line signaling

Signalling integrity protection

379283, 379286, H04M 1100

Patent

active

058898514

ABSTRACT:
An input digital sample containing voice and DTMF signal is used as an input to an adaptive filter. The output signal of the adaptive filter is used to generate a residue from the difference between the input sample and the output signal. The residue signal is used to update the coefficients of the adaptive filter. Upon the convergence of the adaptive filter, the residue signal comprises voice reduced DTMF signal while the adaptive filter's output signal contains the detected DTMF signal.

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S. Haykin, Adaptive Filter Theory, Prentice-Hall, NJ. 1986. pp. 290-291.

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