Tone signal detection apparatus
First Claim
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1. A tone signal detection apparatus, comprising:
- a detecting unit configured to detect a tone signal;
a determining unit configured to receive a detection result from the detecting unit and determine whether the tone signal is present;
a control unit configured to control the determining unit to start and stop tone signal detection;
a time measuring unit configured to measure time during which the tone signal is not detected when a start command is received from the determining unit; and
a time comparing unit configured to compare the measured time with a predetermined threshold value;
wherein the determining unit is configured to determine that the tone signal is present if the measured time is less than the threshold value and report the determination result to the control unit; and
wherein the determining unit is configured to change the threshold value set in the time comparing unit.
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Abstract
A tone signal detection apparatus for detecting a tone signal of a specific frequency is disclosed. The tone signal detection apparatus includes a detecting unit, a determining unit, a time measuring unit, and a time comparing unit. A time during which a signal is not detected by the detecting unit is measured by the time measuring unit, the measured time is compared with a predetermined threshold value by the time comparing unit, and the determining unit determines that signal detection is successful if the measured time is not in excess of the predetermined threshold value.
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3 Claims
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1. A tone signal detection apparatus, comprising:
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a detecting unit configured to detect a tone signal; a determining unit configured to receive a detection result from the detecting unit and determine whether the tone signal is present; a control unit configured to control the determining unit to start and stop tone signal detection; a time measuring unit configured to measure time during which the tone signal is not detected when a start command is received from the determining unit; and a time comparing unit configured to compare the measured time with a predetermined threshold value; wherein the determining unit is configured to determine that the tone signal is present if the measured time is less than the threshold value and report the determination result to the control unit; and wherein the determining unit is configured to change the threshold value set in the time comparing unit. - View Dependent Claims (2, 3)
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Specification