发明名称 |
Inductively coupled keyable control circuit and keying circuit therefore using hybrid detection means |
摘要 |
A keyable control circuit sequentially connects a widely swept fm rf signal to sensing coils at a plurality of detection locations. While rf energy is fed to one of the sensing coils, all other sensing coils are gated off. A resonant detector generates a first signal when an external keying circuit containing a tuned circuit, resonant at a correct first frequency, is inductively coupled to one of the sensing coils. A time-gated envelope detector generates a second signal when the external keying circuit contains a second tuned circuit resonant at a correct second frequency. When the first and second signals are simultaneously present, gating circuits generate a control output signal which may be used to unlock a door or perform other functions access to which is restricted to those possessing keys.
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申请公布号 |
US4056841(A) |
申请公布日期 |
1977.11.01 |
申请号 |
US19760657752 |
申请日期 |
1976.02.13 |
申请人 |
WAGNER ELECTRIC CORPORATION |
发明人 |
ATKINS, CARL E.;MCGUIRK, JR., FRANCIS A. |
分类号 |
G07C11/00;(IPC1-7):H01H47/20;E05B47/00 |
主分类号 |
G07C11/00 |
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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