Signal detection and discrimination using waveform peak factor

An automatic call delivery system for connection to a telephone line comprising:

• 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.

A system for discriminating between the presence in a waveform of signals of a first type and signals of a second type comprising:

• 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.

A method for discriminating between the presence in a waveform of signals of a first type and signals of other types comprising:

• 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.

A method for discriminating between the presence in a waveform of signals of a first type and signals of a second type comprising:

• 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.

A method for discriminating among the presence in a waveform of speech-type signals, single-tone-signals, and double-tone-type signals comprising:

• 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.

A method for discriminating between the presence in a waveform of signals of a first type and signals of a second type comprising:

• 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.