Detecting make-break clicks on a telephone line
First Claim
1. A click detector for detecting a click in a telephone signal, the click detector comprising:
- amplitude sampler means, responsive to the telephone signal, for obtaining measures of magnitude of amplitude of the telephone signal at various points in time;
controller means, responsive to the measures of magnitude from the amplitude sampler means;
(i) (a) for storing the measures of magnitude in a storage means and (b) for sending a magnitude-adaptor signal to a magnitude adaptor for determining a start-of-click adaptive amplitude measure and an end-of-click adaptive amplitude measure and for storing the adaptive amplitude measures in the storage means;
(ii) for determining a measure of time during a reporting interval and for storing the measure of time in the storage means;
the controller means further comprises means, responsive to click-begin information stored in the storage means, for sending a magnitude-jump signal to a magnitude jump detector if the click-begin information indicates a click start has not been detected and, if the click-begin information indicates the click start has been detected, (a) for updating a measure of click length in time and for storing the measure of click length in the storage means and (b) for sending a silence-detect signal to a silence detector;
the controller means still further comprises means, responsive to the measure of time during the reporting interval and to click-detected information stored in the storage means, for generating a click-detection signal which indicates whether a click was detected when the measure of time equals a reporting time interval length;
the magnitude adapter, responsive to the magnitude-adaptor signal, the measures of magnitude, and the start-of-click and the end-of-click adaptive amplitude measures, for updating and storing the adaptive amplitude measures in the storage means;
the magnitude jump detector, responsive to the magnitude-jump signal, measures of magnitude, and the start-of-click adaptive amplitude measure stored in the storage means, for detecting a click start by identifying an increase and a rate of increase in measure of magnitude of amplitude and for updating and storing the click-begin information in the storage means;
the silence detector, responsive to the silence-detect signal, the measures of magnitude, and the end-of-click adaptive amplitude measure stored in the storage means, for;
(a) detecting silence, (b) updating a measure of length of the silence in time and for storing the measure of the length of the silence in the storage means, and (c) sending an end-of-click-detect signal to an end-of-click detector; and
the end-of-click detector, responsive to the end-of-click-detect signal, the measure of click length, and the measure of length of the silence stored in the storage means, for detecting a click end click and for updating and storing the click-detected information in the storage means.
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Accused Products
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.
24 Citations
19 Claims
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1. A click detector for detecting a click in a telephone signal, the click detector comprising:
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amplitude sampler means, responsive to the telephone signal, for obtaining measures of magnitude of amplitude of the telephone signal at various points in time; controller means, responsive to the measures of magnitude from the amplitude sampler means; (i) (a) for storing the measures of magnitude in a storage means and (b) for sending a magnitude-adaptor signal to a magnitude adaptor for determining a start-of-click adaptive amplitude measure and an end-of-click adaptive amplitude measure and for storing the adaptive amplitude measures in the storage means; (ii) for determining a measure of time during a reporting interval and for storing the measure of time in the storage means; the controller means further comprises means, responsive to click-begin information stored in the storage means, for sending a magnitude-jump signal to a magnitude jump detector if the click-begin information indicates a click start has not been detected and, if the click-begin information indicates the click start has been detected, (a) for updating a measure of click length in time and for storing the measure of click length in the storage means and (b) for sending a silence-detect signal to a silence detector; the controller means still further comprises means, responsive to the measure of time during the reporting interval and to click-detected information stored in the storage means, for generating a click-detection signal which indicates whether a click was detected when the measure of time equals a reporting time interval length; the magnitude adapter, responsive to the magnitude-adaptor signal, the measures of magnitude, and the start-of-click and the end-of-click adaptive amplitude measures, for updating and storing the adaptive amplitude measures in the storage means; the magnitude jump detector, responsive to the magnitude-jump signal, measures of magnitude, and the start-of-click adaptive amplitude measure stored in the storage means, for detecting a click start by identifying an increase and a rate of increase in measure of magnitude of amplitude and for updating and storing the click-begin information in the storage means; the silence detector, responsive to the silence-detect signal, the measures of magnitude, and the end-of-click adaptive amplitude measure stored in the storage means, for;
(a) detecting silence, (b) updating a measure of length of the silence in time and for storing the measure of the length of the silence in the storage means, and (c) sending an end-of-click-detect signal to an end-of-click detector; andthe end-of-click detector, responsive to the end-of-click-detect signal, the measure of click length, and the measure of length of the silence stored in the storage means, for detecting a click end click and for updating and storing the click-detected information in the storage means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for detecting a click in a telephone signal, the method comprising the steps of:
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obtaining a measure of magnitude of an amplitude of the telephone signal; determining a start-of-click adaptive amplitude measure and an end-of click adaptive amplitude measure; determining a measure of time during a reporting interval; responsive to stored click-begin information, transferring to a magnitude jump detecting step if the click-begin information indicates a click start has not been detected and, if the click-begin information indicates the click start has been detected, (a) updating a measure of click length in time and (b) transferring to a silence detecting step; wherein the magnitude jump detecting step comprises the steps of;
responsive to a number of measures of magnitude and the start-of-click adaptive amplitude measure, identifying an increase and a rate of increase in measures of magnitude, updating the click-begin information, and transferring to a reporting step;wherein the silence detecting step comprises the steps of;
responsive to the measure of magnitude and the end-of-click adaptive amplitude measure, detecting silence, determining a measure of length of the silence, determining the end of a click, and setting click-detected information;wherein the reporting step comprises the step of, responsive to the measure of time and the click-detected information, generating a click-detection signal which indicates whether a click was detected when the measure of time equals a reporting time interval length.
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12. A click detector for detecting a click in a telephone signal, the click detector comprising:
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amplitude sampler means, responsive to the telephone signal, for;
(a) obtaining a measure of magnitude of an amplitude of the telephone signal and storing the measure in a storage means;
(b) determining a start-of-click and an end-of-click adaptive amplitude measure and for storing the adaptive measures in the storage means;
(c) determining a measure and for storing the measure of time in the storage means;
(d) responsive to click-begin information stored in the storage means, sending a magnitude jump signal to a magnitude jump detector if the click-begin information indicates a click start has not been detected and, if the click-begin information indicates the click start has been detected, (i) for updating a measure of click length in time and for storing the measure of click length in the storage means; and
(ii) for sending a silence-detect signal to a silence detector; and
(e) responsive to the measure of time during the reporting interval and to click-detected information stored in the storage means, generating a click-detection signal which indicates whether a click was detected when the measure of time equals a reporting time interval length;the magnitude jump detector, responsive to the magnitude jump signal, measures of magnitude, and the start-of-click adaptive amplitude measure stored in the storage means, for detecting a click start by identifying an increase and a rate of increase in measure of magnitude of amplitude and for updating and storing the click-begin information signal in the storage means; the silence detector, responsive to the silence-detect signal, the measure of magnitude, the end-of-click adaptive amplitude measure and the measure of click length stored in the storage means, for;
(a) detecting silence, (b) updating a measure of length of the silence in time and for storing the measure of the length of silence in the storage means, and (c) detecting an end of a click and for updating and storing the click-detected information in the storage means.
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13. A click detector for detecting a click in a telephone signal, the click detector comprising:
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magnitude jump detector, responsive to the telephone signal, for;
(a) obtaining a measure of magnitude of an amplitude of the telephone signal and storing the measure in a storage means, (b) determining a start-of-click and an end-of-click adaptive amplitude measure and storing the adaptive amplitude measures in the storage means, (c) responsive to the measure, the start-or-click adaptive amplitude measure, and other measures obtained from the storage means, for identifying an increase and a rate of increase in measure of magnitude of amplitude to detect a click start and for storing an indication thereof as click begin information in the storage means; and
(d) transmitting a signal to a controller means;silence detector, responsive to the telephone signal and to the end-of-click adaptive amplitude measure stored in the storage means, for;
(a) detecting silence, (b) determining a measure of length of the silence in time and for storing the measure of the length in the storage means, and (c) responsive to the measure of length of the silence, for detecting a click end and for storing an indication thereof as click-end information in the storage means;wherein the controller means, responsive to the signal from the magnitude jump detector, comprises means for;
(a) determining a measure of time during a reporting interval and for storing the measure of time in the storage means;
(b) responsive to the click-begin and click-end information stored in the storage means, updating a measure of click length in time and storing an indication that the click is detected in the storage means if the measure of click length is less than a predetermined length; and
(c) if the measure of time during the reporting interval exceeds a predetermined length of time, generating a click-detection signal which indicates whether a click was detected during the reporting interval.
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14. A click detector for detecting a click in a telephone signal, the click detector comprising:
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means for obtaining a measure of magnitude of amplitude of the telephone signal; means, responsive to the measure of magnitude of amplitude, for determining a start-of-click and an end-of-click adaptive amplitude measure; click-begin means, if click-begin information indicates that a click start has not been detected, for testing whether the measure of magnitude exceeds the start-of-click adaptive amplitude measure, for testing whether a rate of increase in measure of magnitude exceeds a rate-of-increase threshold, and, if the tests are satisfied, for updating the click-begin information to indicate detection of the click start; and click-end means, if the click-begin information indicates that a click start has been detected, for updating a measure of click length in time, for testing whether measures of magnitude are less than the end-of-click adaptive amplitude for predetermined length of time and, if the test is satisfied, for determining the measure of click length, and for generating a click detection signal if the measure of click length is less than a predetermined length. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification