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US 2003/0223572 A1Published application
Apparatus and method for detecting a tone disconnect signal in the presence of voice
OwnerLarry John Roybalinventor
Life of this patent
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Abstract
Energy cadence detector detects a signaling tone in the presence of voice by requiring multiple cycles of the tone to be detected before detection is indicated.
Claims15
A method for detecting a signaling tone in the presence of voice in a signal, comprising the steps of:
- (a) converting the signal to a cadence signal;
- (b) detecting for a complete cycle of the signaling tone in the cadence signal;
- (c) incrementing a count of complete cycles of the signaling tone detected upon a complete cycle having been detected in the step (b);
- (d) comparing the count with a predefined value;
- (e) repeating the steps (b), (c), and (d) if the count is less than the predefined value;
- and
- (f) indicating that the signaling tone has been detected if the count is equal to or greater than the predefined value.
4 more elements
A method for detecting a signal in the presence of voice, comprising the steps of:
- in response to receiving a signal comprising a cadence of signal-on intervals interleaved with signal-off intervals, measuring durations of sequential ones of the signal-on intervals and measuring durations of sequential ones of the signal-off intervals;
- incrementing a count for each pair of signal-on and signal-off intervals;
- using sequential measured signal-on interval durations in a sequence of a plurality of first tables each corresponding to a different signal-on interval in the cadence and having a plurality of entries, each entry corresponding to a different duration of the corresponding signal-on interval and identifying signals which have the corresponding signal-on interval duration as candidates for the received signal, to select the corresponding entries from sequential ones of the first tables;
- using sequential measured signal-off interval durations in a sequence of a plurality of a second tables each corresponding to a different signal-off interval in the cadence and having a plurality of entries, each entry corresponding to a different duration of the corresponding signal-off interval and identifying signals which have the corresponding signal-off interval duration as candidates for the received signal, to select the corresponding entries from sequential ones of the second tables;
- comparing together the entries selected from the first and the second tables to determine a single signal that is identified by each of the selected entries as a candidate for the received signal;
- and
- indicating the received signal to be the determined candidate if the count equals a predefined value.
4 more elements
An apparatus for detecting a signaling tone in the presence of voice in a signal, comprising:
- a energy detector responsive to the signal for producing a cadence signal having signal-on intervals and signal-off intervals;
- a counter for counting complete cycles of the signaling tone;
- a cadence detector responsive to the detection of a complete cycle of the signaling tone for incrementing the counter;
- and
- the counter indicating detection of the signaling tone upon the counter equaling a predefined value.
2 more elements
Dependencies are inferred from the claim text.