TONE DETECTION CONFIRMATION METHOD

Title:

TONE DETECTION CONFIRMATION METHOD

Document Type and Number:

Japanese Patent JPH0819008

Kind Code:

A

Abstract:

PURPOSE: To provide a method and a device for setting talk-off and the erroneous detection of tone to be minimum. CONSTITUTION: A first recognition circuit 12 uses remaining energy which is not accounted by linear prediction encoding for the special order of a model as reference for validity-deciding (30) whether valid tone or digit is received or not. A second recognition circuit 14 operating with the first recognition circuit 12 uses discrete Fourier transformation (38) in frequencies in the center of or adjacent to an energy peak related to tone. The ratios (40 and 42) of peak energy against adjacent energy are used for deciding (48) validity with the corresponding thresholds (44 and 46). The reliability of a high level can be obtained by detecting special tone or digit by a digit deciding circuit 10.

Inventors:

JIEFUREI UEIN DAAHAATEI
RICHIYAADO HARII KETSUCHIYUMU

Application Number:

JP16132695A

Publication Date:

January 19, 1996

Filing Date:

June 28, 1995

Export Citation:

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Assignee:

AT & T CORP

International Classes:

H04Q9/00; H04Q1/45; H04Q1/457; H04Q1/46; (IPC1-7): H04Q1/45; H04Q9/00

Attorney, Agent or Firm:

Masao Okabe (2 outside)

Next Patent: INITIALIZATION CIRCUIT FOR SUBSCRIBER CIRCUIT