| 摘要 |
An absorption detector for determining nuclear magnetic resonance with automatic frequency control. The detector comprises a sample holder including coils, a reference oscillator including a tank circuit being coupled to these coils. A magnet is provided including modulating coils and power coils and having a gap in which the holder is positioned. The oscillator includes a low-noise amplifier and impedor, and a limiter connected in feedback relation with the amplifier via the impedor. A low-frequency amplifier is provided and a synchronous detector is coupled via the low-frequency amplifier to the low-frequency amplifier. An XY recorder is coupled to the synchronous detector, and a modulating oscillator is coupled to the modulating coils, the reference oscillator and the synchronous detector. A power supply is coupled to the power coils and to the XY recorder to determine the X position of the latter. An automatic control is provided which is coupled to the reference oscillator to control the frequency thereof.
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