Adaptive method and apparatus for detecting a stutter dial tone signal
First Claim
Patent Images
1. A method of detecting a stutter dial tone SDT signal, the method comprising the steps of:
- a) receiving a received signal from a subscriber loop;
b) generating a signal envelope of said received signal;
c) generating a threshold parameter value from said signal envelope;
c) counting the number of threshold parameter crossings undertaken by said signal envelope; and
d) producing a signal indicating said SDT signal has been received when said number of threshold crossings exceeds a predefined value.
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Abstract
A method and apparatus for detecting a stutter dial tone SDT signal. The method includes the steps of, receiving a received signal from a subscriber loop, generating a signal envelope of the received signal, generating a threshold parameter value from the signal envelope, counting the number of threshold parameter crossings undertaken by the signal envelope and producing a signal indicating SDT signal has been received when number of threshold crossings exceeds a predefined value.
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Citations
56 Claims
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1. A method of detecting a stutter dial tone SDT signal, the method comprising the steps of:
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a) receiving a received signal from a subscriber loop; b) generating a signal envelope of said received signal; c) generating a threshold parameter value from said signal envelope; c) counting the number of threshold parameter crossings undertaken by said signal envelope; and d) producing a signal indicating said SDT signal has been received when said number of threshold crossings exceeds a predefined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of signalling a telephone in communication with a subscriber loop, the method comprising the steps of:
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a) transmitting a stutter dial tone SDT signal on said subscriber loop; b) receiving said stutter dial tone signal from said subscriber loop; c) generating a signal envelope of said stutter dial tone signal; d) generating a threshold parameter value from said signal envelope; e) counting the number of threshold parameter crossings undertaken by said signal envelope; and f) producing a signal indicating said SDT signal has been received when said number of threshold crossings exceeds a predefined value.
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18. An apparatus for detecting a stutter dial tone SDT signal, the apparatus comprising:
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a) a receiver for receiving a signal envelope from subscriber loop; b) a detector for generating a signal envelope of said received signal; c) a threshold parameter generator for generating a threshold parameter value from said signal envelope; d) a counter for counting the number of threshold parameter crossings undertaken by said signal envelope; and e) an SDT detect signal generator for generating a signal indicating said SDT signal has been received when said number of threshold crossings exceeds a predefined value. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A system for signalling a telephone in communication with a subscriber loop, the system comprising:
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a) a transmitter for transmitting a stutter dial tone SDT signal on said subscriber loop; b) a receiver at said telephone for receiving said stutter dial tone signal at said telephone; c) a detector for detecting a signal envelope of said stutter dial tone signal; d) a threshold parameter signal generator for generating a threshold parameter value from said signal envelope; e) a counter for counting the number of threshold parameter crossings undertaken by said signal envelope; and f) an SDT detect signal generator for generating a signal indicating said SDT signal has been received when said number of threshold crossings exceeds a predefined value.
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35. An apparatus for detecting a stutter dial tone SDT signal, the apparatus comprising:
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a) means for receiving a received signal from said subscriber loop; b) means for generating a signal envelope from said received signal; c) means for generating a threshold parameter value from said signal envelope; d) means for counting the number of threshold parameter crossings undertaken by said signal envelope; and e) means for producing a signal indicating said SDT signal has been received when said number of threshold crossings exceeds a predefined value. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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54. A system for signalling a telephone in communication with a subscriber loop, the system comprising:
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a) means for transmitting a stutter dial tone SDT signal on said subscriber loop; b) means for receiving said stutter dial tone signal from said subscriber loop; b) means for generating a signal envelope from said stutter dial tone signal; c) means for generating a threshold parameter value from said signal envelope; d) means for counting the number of threshold parameter crossings undertaken by said signal envelope; and e) means for producing a signal indicating said SDT signal has been received when said number of threshold crossings exceeds a predefined value. - View Dependent Claims (55, 56)
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Specification