| 摘要 |
An electronic interface (10) between a pure NMR receiver resonator (RO) and a preamplifier matches the impedance of the resonator to the preamplifier during the receiving process and decouples the resonator during the transmitting process. For opening or detuning the resonator one or more switching diodes (Dopen) are provided, through which a current flows during the transmitting process, and one or more control diodes (Dmatch1, Dtune1) are provided through which the current flows to the switching diodes. The control diodes are connected to the switching diodes directly or via one or more additional series impedances. The impedance of the resonator is transformed to the required preamplifier or line impedance during the receiving process with little loss. The control diodes (Dmatch1, Dtune1) may be varactor diodes and the switching diode may be a PIN diode. An additional protective diode (DDC) protects the switching diode from high current. |
