发明名称 |
CAPACITIVE KEYSWITCH SENSOR AND METHOD |
摘要 |
<p>Each of the inputs of an analog multiplexer are connected to a plurality of capacitive keyswitches and a reference capacitor. At the first multiplexer scan position, the reference capacitor is charged through a charging resistor and when a predetermined voltage is reached a threshold amplifier is caused to respond. The time period required to charge the reference capacitor is stored and compared with the time period required to charge each of the keyswitches. A control signal is generated in response to this comparison providing a signal representative of the capacitive value of the keyswitch in relation to the reference capacitor and thus the operative condition of the keyswitch.</p> |
申请公布号 |
CA1013819(A) |
申请公布日期 |
1977.07.12 |
申请号 |
CA19740207305 |
申请日期 |
1974.08.19 |
申请人 |
TELETYPE CORPORATION |
发明人 |
MARIN, ROBERT E.;SIMONSON, ROGER K. |
分类号 |
G06F3/02;H01H13/00;H03K17/975;H03K17/98;H03M11/02 |
主分类号 |
G06F3/02 |
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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