Signal detection and discrimination using waveform peak factor
First Claim
1. A call progress analyzer comprising:
- means for receiving waveforms from a telephone line;
means defining a peak factor range, said range being associated with a particular signal type;
measuring means for determining whether peak factors of waveforms received from the telephone line fall within said range and for providing a signal-type indication of said particular signal type in response to a determination that a peak factor falls within said range;
call status decision logic for receiving said signal-type indication and for determining call status.
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Accused Products
Abstract
Apparatus and method for detecting and discriminating among various signals indicative of progress while making a telephone connection. A particular waveform parameter known as peak factor is advantageously employed in a call progress analyzer. The illustrative call progress analyzer uses the average magnitude peak factor (ratio of the peak of the waveform to the average of the absolute value of the waveform) to distinguish among single-tone signals (e.g., special service information tones), double-tone signals (e.g., dial tone, audible ring, and busy), and speech. Waveform ON and OFF times (duration above and below an energy threshold) are combined with signal-type determinations (made using peak factor) to automatically determine the status of a call.
68 Citations
41 Claims
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1. A call progress analyzer comprising:
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means for receiving waveforms from a telephone line; means defining a peak factor range, said range being associated with a particular signal type; measuring means for determining whether peak factors of waveforms received from the telephone line fall within said range and for providing a signal-type indication of said particular signal type in response to a determination that a peak factor falls within said range; call status decision logic for receiving said signal-type indication and for determining call status. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An automatic call delivery system for connection to a telephone line comprising:
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means for initiating a telephone call, including means for placing the telephone line in an off-hook condition and means for dialing a telephone number; means for defining at least first and second peak factor ranges, said ranges being associated with first and second signal types, respectively; peak factor determination means for determining whether peak factors of waveforms received from the telephone line fall within either of said ranges and for providing a signal-type indication of the associated signal type in response to a determination that a peak factor falls within one of said ranges; delivery indication means for receiving said signal-type indications and for indicating that a call has been answered. - View Dependent Claims (12, 13, 14, 15)
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16. A system for discriminating between the presence in a waveform of signals of a first type and signals of other types comprising:
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means defining a peak factor range associated with signals of the first type; measuring means, adapted to receive a representation of the waveform, for making at least one determination of peak factor of the waveform; indicating means, responsive to the measuring means and to the range defining means, for indicating the presence of a signal of the first type when the determined peak factor is within the defined range. - View Dependent Claims (17)
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18. A system for discriminating between the presence in a waveform of speech-type signals and signals of other types comprising:
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means defining a peak factor range associated with speech-type signals; measuring means, adapted to receive a representation of the waveform, for making at least one determination of peak factor of the waveform; indicating means, responsive to the measuring means and to the range defining means, for indicating the presence of a speech-type signal when the determined peak factor is within the defined range. - View Dependent Claims (19)
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20. A system for discriminating between the presence in a waveform of speech-type signals and tone-type signals comprising:
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means defining a first peak factor range associated with speech-type signals and defining a second peak factor range associated with tone-type signals; measuring means, adapted to receive a representation of the waveform, for making at least one determination of peak factor of the waveform; indicating means, responsive to the measuring means and to the range defining means, for indicating the presence of a speech-type signal when the determined peak factor is within the first defined range and indicating the presence of a tone-type signal when the peak factor is within the second defined range. - View Dependent Claims (21)
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22. A system for discriminating between the presence in a waveform of single-tone signals and double-tone signals comprising:
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means defining a first peak factor range associated with single-tone signals and defining a second peak factor range associated with tone-type signals; measuring means, adapted to receive a representation of the waveform, for making at least one determination of peak factor of the waveform; indicating means, responsive to the measuring means and to the range defining means, for indicating the presence of a speech-type signal when the determined peak factor is within the first defined range and indicating the presence of a tone-type signal when the peak factor is within the second defined range. - View Dependent Claims (23)
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24. A system for discriminating among the presence in a waveform of speech siganls, double-tone signals, and single-tone signals comprising:
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means defining, a first peak factor range associated with speech signals, defining a second peak factor range associated with double-tone signals, and defining a third peak factor range associated with single-tone singals; measuring means, adapted to receive a representation of the waveform, for making at least one determination of peak factor of the waveform; indicating means, responsive to the measuring means and to the range defining means, for indicating the presence of a speech signal when the determined peak factor is within the first defined range, indicating the presence of a double-tone signal when the peak factor is within the second defined range, and indicating the presence of a single-tone signal when the peak factor is within the third defined range. - View Dependent Claims (25, 26)
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27. A system for discriminating between the presence in a waveform of signals of a first type and signals of a second type comprising:
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means for receiving a waveform and for creating a series of digital samples representing the waveform; means defining measurement intervals and for associating samples with the measurement intervals; peak measurement means for determining the peak sample value for each measurement interval; signal level measurement means for making a signal level determination for each measurement interval; means for defining a peak factor range characteristic of signals of the first type and for defining a peak factor range characteristic of signals of the second type; scaling means for scaling the signal level determination according to scale factors characteristic of peak factor ranges; means for comparing the determined peak value with the scaled forms of signal level and for producing signal-type determinations. - View Dependent Claims (28, 29, 30, 31)
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32. A method of determining the progress of a call comprising:
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receiving waveforms from a telephone line; making peak factor measurements of the received waveforms; determining call status using the peak factor measurements. - View Dependent Claims (33)
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34. A method for discriminating between the presence in a waveform of signals of a first type and signals of other types comprising:
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defining a peak factor range associated with signals of the first type; receiving a representation of the waveform; making a determination of peak factor of the waveform; indicating the presence of a signal of the first type when the determined peak factor is within the defined range. - View Dependent Claims (35)
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36. A method for discriminating between the presence in a waveform of signals of a first type and signals of a second type comprising:
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defining first and second peak factor ranges associated with signals of the first type and signals of the second type, respectively; receiving a representation of the waveform; making a determination of peak factor of the waveform; indicating the presence of a signal of the first type when the determined peak factor is within the first range and indicating the presence of a signal of the second type when the peak factor is within the second range. - View Dependent Claims (37, 38)
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39. A method for discriminating among the presence in a waveform of speech-type signals, single-tone-signals, and double-tone-type signals comprising:
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defining first, second, and third peak factor ranges associated with speech-type, single-tone-type, and double-tone-type tone-type signals, respectively; receiving a representation of the waveform; making a determination of peak factor of the waveform; indicating the presence of a speech-type signal when the determined peack factor is within the first range, indicating the presence of a single-tone-type signal when the peak factor is within the second range, and indicating the presence of a double-tone-type signal when the peak factor is within the third range.
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40. A method for discriminating between the presence in a waveform of signals of a first type and signals of a second type comprising:
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defining first and second peak factor ranges associated with signals of the first type and signals of the second type, respectively; creating a series of digital samples representing an interval of the waveform; determining the peak sample value for the interval; making a signal level determination for the interval; comparing the peak factor of the interval with the peak factor ranges. - View Dependent Claims (41)
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Specification