Importance

Loading Importance Indicators...

Abstract

Method and apparatus for detecting make-break clicks on a telephone line, i.e., clicks produced by going on-hook or off-hook. A click is detected by analyzing time slices of a telephone signal to detect a sharp positive transition in signal energy followed by a diminishing envelope of short duration. Three signal measures are utilized to determine whether a click has occurred: (a) a magnitude transition, i.e., a change of the magnitude of the amplitude of the signal over a short period of time; (b) a peak magnitude, i.e., a magnitude of the amplitude of the signal corresponding to the first acceptably large magnitude transition (the beginning of the click); and (c) a duration of the signal envelope. In accordance with the present invention: (a) the minimum allowable peak magnitude of a valid click is scaled to the maximum magnitude encountered as the telephone signal is analyzed, i.e., a start-of-click adaptive amplitude measure, and (b) the end of the click is determined by comparing the magnitude of the amplitude of the signal with a maximum allowable magnitude for silence which is scaled to the maximum magnitude encountered since the last click ended, i.e., an end-of-click adaptive amplitude measure.

Loading the Abstract Image...

First Claim