Method for detecting single frequency tones
OwnerJames Seidman, Douglas Rylaarsdaminventors
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Abstract
A method and apparatus are provided for detecting a relatively constant frequency signal on a communication channel. The method includes the steps of detecting sign changes of the signal on the channel and determining that the signal is substantially the only signal present on the channel when an average time interval between positive-going sign changes substantially equals an average time interval between negative-going sign changes.
Claims30
A method of detecting a relatively constant frequency signal on a communication channel, such method comprising:
- detecting sign changes of the signal on the channel;
- and
- determining that the signal is substantially the only signal present on the channel when an average time interval between positive-going sign changes substantially equals an average time interval between negative-going sign changes.
An apparatus for detecting a relatively constant frequency signal on a communication channel, such apparatus comprising:
- means for detecting sign changes of the signal on the channel;
- and
- means for determining that the signal is substantially the only signal present on the channel when an average time interval between positive-going sign changes substantially equals an average time interval between negative-going sign changes.
An apparatus for detecting a relatively constant frequency signal on a communication channel, such apparatus comprising:
- a sign detection processor that detects sign changes of the signal on the channel;
- and
- a comparator that determines that the signal is substantially the only signal present on the channel when an average time interval between positive-going sign changes substantially equals an average time interval between negative-going sign changes.
Dependencies are inferred from the claim text.