发明名称 |
Use of telemetry coil to replace magnetically activated reed switch in implantable devices |
摘要 |
A combined telemetry system and magnetic field sensor for use in an implantable medical device. The telemetry system includes a conventional resonant circuit for transmitting and receiving data. The resonant circuit has a coil which is also used to sense the presence of a magnetic field exceeding a threshold value. The resonant frequency varies with the strength of the magnetic field which passes through the coil. Periodically, the resonant circuit is energized, and during a sensing window of predetermined duration which then immediately follows the voltage across the coil is examined for a predetermined number of zero crossings. That number of zero crossings will occur only in the presence of a magnetic field whose amplitude exceeds the threshold value. It is possible to achieve a sensitivity in such a system which is comparable to that of conventional miniature reed switches.
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申请公布号 |
US4541431(A) |
申请公布日期 |
1985.09.17 |
申请号 |
US19840652290 |
申请日期 |
1984.09.20 |
申请人 |
TELECTRONICS PTY. LTD. |
发明人 |
IBRAHIM, IBRAHIM H.;DALY, CHRISTOPHER N. |
分类号 |
A61N1/36;A61N1/372;(IPC1-7):A61N1/36 |
主分类号 |
A61N1/36 |
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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