Apparatus and methods for electrical signal discrimination

Claim 1

A method for distinguishing between voice signals and system-generated audio signals in an electrical audio device, the method comprising the steps of: digitizing an electrical audio signal so as to generate a series of uniform high voltage signals and uniform low voltage signals; sampling said digitized electrical audio signal so as to obtain a plurality of samples; analyzing the digitized electrical audio samples to determine whether the digitized audio signal has a regular periodic pattern; and generating an electrical signal in response to the analyzing step to indicate whether voice signals are present in the electrical audio device.

Claim 2

A method for distinguishing between voice signals and system-generated audio signals in an electrical audio device, the method comprising the steps of: digitizing an electrical audio signal so as to generate a series of uniform high voltage signals and uniform low voltage signals; sampling said digitized electrical audio signal so as to obtain a plurality of samples; analyzing the digitized electrical audio samples to determine whether the digitized audio signal has a regular periodic pattern; and generating an electrical signal in response to the analyzing step to indicate whether voice signals are present in the electrical audio device.

Claim 9

A method for distinguishing between voice signals and system-generated audio signals in an electrical audio device, the method comprising the steps of: (1) digitizing a system-generated audio signal so as to generate a series of uniform high voltage signals and uniform low voltage signals; (2) sampling the digitized audio signal during successive time periods; (3) establishing a comparison standard during a first time period; (4) comparing the digitized audio signal which is sampled during time periods subsequent to said first time period with the comparison standard established during said first time period so as to determine that the digitized system-generated audio signal has a regular periodic pattern; (5) generating a first electrical signal in response to steps (2-) (4); (6) digitizing a random audio signal so as to generate a series of uniform high voltage signals and uniform low voltage signals; (7) determining that the digitized random audio signal does not have a regular periodic pattern; and (8) generating a second electrical signal in response to step (7).

Claim 10

A method for distinguishing between voice signals and system-generated audio signals in an electrical audio device, the method comprising the steps of: (1) digitizing a system-generated audio signal so as to generate a series of uniform high voltage signals and uniform low voltage signals; (2) sampling the digitized audio signal during successive time periods; (3) establishing a comparison standard during a first time period; (4) comparing the digitized audio signal which is sampled during time periods subsequent to said first time period with the comparison standard established during said first time period so as to determine that the digitized system-generated audio signal has a regular periodic pattern; (5) generating a first electrical signal in response to steps (2-) (4); (6) digitizing a random audio signal so as to generate a series of uniform high voltage signals and uniform low voltage signals; (7) determining that the digitized random audio signal does not have a regular periodic pattern; and (8) generating a second electrical signal in response to step (7).

Claim 16

A method for electrical signal discrimination, the method comprising the steps of: (1) digitizing an electrical signal; (2) sampling the digitized electrical signal during successive time periods; (3) establishing a first comparison standard during a first time period; (4) comparing the digitized electrical signal which is sampled during time periods subsequent to said first time period with said first comparison standard; and (5) generating an output signal whenever the digitized electrical signal which is sampled during a preselected number of said subsequent time periods varies from the first comparison standard by more than a predetermined amount.

Claim 17

A method for electrical signal discrimination, the method comprising the steps of: (1) digitizing an electrical signal; (2) sampling the digitized electrical signal during successive time periods; (3) establishing a first comparison standard during a first time period; (4) comparing the digitized electrical signal which is sampled during time periods subsequent to said first time period with said first comparison standard; and (5) generating an output signal whenever the digitized electrical signal which is sampled during a preselected number of said subsequent time periods varies from the first comparison standard by more than a predetermined amount.

Claim 27

A method for electrical signal discrimination, the method comprising the steps of: (1) digitizing an electrical signal so as to generate a series of uniform high voltage signals and uniform low voltage signals by means of at least one of the following: generating a high voltage signal whenever the instantaneous voltage level of the electrical signal is greater than a specified reference value and generating a low voltage signal at all other times; and generating a high voltage signal whenever the instantaneous slope of the electrical signal is positive and generating a low voltage signal at all other times; (2) sampling the digitized electrical signal during successive time periods by determining at least one of the following: the number of times during each time period that a transition occurs in the digitized electrical signal from a low voltage signal to a high voltage signal; and the amount of time in each time period during which the digitized electrical signal is a high voltage signal; (3) establishing a first comparison standard during a first time period; (4) comparing the digitized electrical signal which sampled during time periods subsequent to said first time period with the first comparison standard; and (5) generating an output signal whenever the digitized electrical signal during a preselected number of said subsequent time periods varies from the first comparison standard by more than a predetermined amount.

Claim 28

A method for electrical signal discrimination, the method comprising the steps of: (1) digitizing an electrical signal so as to generate a series of uniform high voltage signals and uniform low voltage signals by means of at least one of the following: generating a high voltage signal whenever the instantaneous voltage level of the electrical signal is greater than a specified reference value and generating a low voltage signal at all other times; and generating a high voltage signal whenever the instantaneous slope of the electrical signal is positive and generating a low voltage signal at all other times; (2) sampling the digitized electrical signal during successive time periods by determining at least one of the following: the number of times during each time period that a transition occurs in the digitized electrical signal from a low voltage signal to a high voltage signal; and the amount of time in each time period during which the digitized electrical signal is a high voltage signal; (3) establishing a first comparison standard during a first time period; (4) comparing the digitized electrical signal which sampled during time periods subsequent to said first time period with the first comparison standard; and (5) generating an output signal whenever the digitized electrical signal during a preselected number of said subsequent time periods varies from the first comparison standard by more than a predetermined amount.

Claim 33

An apparatus for detecting that a called telephone has been answered, comprising: an audio detector device connected to a set of telephone lines; a digitizer for transforming electrical audio signals on the telephone lines into a series of uniform high voltage signals and uniform low voltage signals; and a digital computing device comprising means for obtaining a plurality of samples from the digitizer, means for storing a comparison standard and comparing successive samples to the comparison standard, and means for analyzing said samples so as to determine whether the output signals from the digitizer represent electrical audio signals having a regular or random pattern.

Claim 34

An apparatus for detecting that a called telephone has been answered, comprising: an audio detector device connected to a set of telephone lines; a digitizer for transforming electrical audio signals on the telephone lines into a series of uniform high voltage signals and uniform low voltage signals; and a digital computing device comprising means for obtaining a plurality of samples from the digitizer, means for storing a comparison standard and comparing successive samples to the comparison standard, and means for analyzing said samples so as to determine whether the output signals from the digitizer represent electrical audio signals having a regular or random pattern.

Claim 41

A method for distinguishing between voice signals and system-generated audio signals in an electrical audio device, the method comprising the steps of: digitizing an electrical audio signal so as to generate a series of uniform high voltage signals and uniform low voltage signals; sampling the digitized audio signal during successive time periods; establishing a comparison standard during a first time period; comparing the digitized audio signal which is sampled during the time periods subsequent to said first time period with the comparison standard established during said first time period to determine whether the digitized audio signal has a regular periodic pattern; and generating an electrical signal in response to the analyzing step to indicate whether voice signals are present in the electrical audio device.

Claim 42

A method for distinguishing between voice signals and system-generated audio signals in an electrical audio device, the method comprising the steps of: digitizing an electrical audio signal so as to generate a series of uniform high voltage signals and uniform low voltage signals; sampling the digitized audio signal during successive time periods; establishing a comparison standard during a first time period; comparing the digitized audio signal which is sampled during the time periods subsequent to said first time period with the comparison standard established during said first time period to determine whether the digitized audio signal has a regular periodic pattern; and generating an electrical signal in response to the analyzing step to indicate whether voice signals are present in the electrical audio device.

Claim 43

An apparatus for detecting that a called telephone has been answered, comprising: an audio detector device connected to a set of telephone lines; a digitizer for transforming electrical audio signals on the telephone lines into a series of uniform high voltage signals and uniform low voltage signals, the digitizer comprising a frequency source; a switching means connected to the frequency source such that the switching means successively opens and closes at the frequency of said frequency source; a sample and hold means connected to the switching means such that the sample and hold means is charged to the instantaneous voltage level of the electrical audio signals whenever the switching means is open; and a voltage comparator which produces a high voltage signal whenever the instantaneous voltage level of the electrical audio signals is greater than the voltage across the sample and hold means and which produces a low voltage signal at all other times, whereby a high voltage signal is generated whenever the instantaneous slope of the electrical audio signals is positive and a low voltage signal is generated at all other times; and a digital computing device for sampling and analyzing output signals from both the audio detector and the digitizer so as to determine whether the output signals from the digitizer represent electrical audio signals on the telephone lines having a regular periodic pattern.

Claim 44

An apparatus for detecting that a called telephone has been answered, comprising: an audio detector device connected to a set of telephone lines; a digitizer for transforming electrical audio signals on the telephone lines into a series of uniform high voltage signals and uniform low voltage signals, the digitizer comprising a frequency source; a switching means connected to the frequency source such that the switching means successively opens and closes at the frequency of said frequency source; a sample and hold means connected to the switching means such that the sample and hold means is charged to the instantaneous voltage level of the electrical audio signals whenever the switching means is open; and a voltage comparator which produces a high voltage signal whenever the instantaneous voltage level of the electrical audio signals is greater than the voltage across the sample and hold means and which produces a low voltage signal at all other times, whereby a high voltage signal is generated whenever the instantaneous slope of the electrical audio signals is positive and a low voltage signal is generated at all other times; and a digital computing device for sampling and analyzing output signals from both the audio detector and the digitizer so as to determine whether the output signals from the digitizer represent electrical audio signals on the telephone lines having a regular periodic pattern.