发明名称 |
DTMF signal judging apparatus |
摘要 |
A DTMF signal judging apparatus includes a first power calculator, and second power calculator and a judging apparatus. The first power calculator calculates the overall power of an input signal or the power of the input signal outside the DTMF frequency band. The second power calculator calculates the power in the DTMF frequency band; or more specifically, calculates the power in both the higher and lower frequency band portions of the DTMF frequency band. The judging apparatus then compares the output from the first and second calculators, and determines whether the input signal is a DTMF signal based on the comparison.
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申请公布号 |
US5592544(A) |
申请公布日期 |
1997.01.07 |
申请号 |
US19950451049 |
申请日期 |
1995.05.25 |
申请人 |
SHARP KABUSHIKI KAISHA |
发明人 |
MURATA, YASUMOTO;IKEUCHI, MICHIO;YOSHIKAWA, SHUICHI;WATANABE, MASAHIKO |
分类号 |
H04Q1/453;(IPC1-7):H04M1/515 |
主分类号 |
H04Q1/453 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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