发明名称 |
Method and apparatus for detection of a telephone CPE alerting signal |
摘要 |
A method and apparatus for detecting a signaling tone within a communications channel, such as a telephone line, is presented. The energy level of the communications channel signal is measured at the frequency of the signaling tone and at one or more frequencies that are integer divisors of the signaling tone (i.e. at one or more subharmonics). The subharmonic energies are evaluated in determining whether the signaling tone is present. The technique can be implemented using a plurality of resonators and a comparator.
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申请公布号 |
US6940966(B2) |
申请公布日期 |
2005.09.06 |
申请号 |
US20020079969 |
申请日期 |
2002.02.21 |
申请人 |
VTECH TELECOMMUNICATIONS, LTD. |
发明人 |
LEE JULIAN;LOUIE GARY |
分类号 |
H04M1/57;H04M15/06;(IPC1-7):H04M3/22 |
主分类号 |
H04M1/57 |
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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