发明名称 |
PROTECTIVE CIRCUIT FOR THE INPUT TRANSISTOR OF A RECEPTION AMPLIFIER IN NUCLEAR MAGNETIC RESONANCE SYSTEMS |
摘要 |
A reception amplifier in a nuclear magnetic resonance system includes an input transistor. The base of the input transistor is connected to a protective circuit. The protective circuit shifts the voltage at the base-emitter path of the input transistor into the inhibit range only during a high-frequency transmission pulse. The voltage is produced by rectification of a fraction of the high-frequency transmission pulse. The protective circuit of the reception pre-amplifier prevents the input transistor from being gradually destroyed by an excessive base current during the transmission when voltage peaks are provided at the input.
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申请公布号 |
US5194825(A) |
申请公布日期 |
1993.03.16 |
申请号 |
US19910736645 |
申请日期 |
1991.07.26 |
申请人 |
SIEMENS AKTIENGESELLSCHAFT |
发明人 |
ZAMETZER, KLAUS;VESTER, MARKUS |
分类号 |
H03F1/52;G01R33/36;H03K17/0812;H04B1/18 |
主分类号 |
H03F1/52 |
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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