| 摘要 |
<p>A device to detect magnetic resonance in the time domain that includes a radiofrequency (RF) source (46), having an output connected to a transmitter (47) the output of which is fed to a probe-preamplifier (48). The signal output of the probe-preamplifier is connected to the input of a filter (49) the output of which is connected to the input of a phase-sensitive detector (50). Another input of the phase-sensitive detector is connected to a second output of the RF source (46), with the output of the phase-sensitive detector being connected to the input of a digitizer (51). The output of the digitizer is connected to a computer (52). The device of the present invention works on the basis of phase coherent frequency switching, making use of the fact that signal excitation and detection occur in distinct time intervals in time domain magnetic resonance experiments. In operating the device of the present invention, the transmitter is positioned at the centre of the spectral window; after the pulse irradiation at this frequency to excite the sample, the receiver reference frequency is shifted phase coherently, during the receiver dead time, by one half the desired spectral width, to coincide with one extreme of the spectral window. <IMAGE></p> |
