| 摘要 |
PURPOSE:To eliminate the ghost of two-dimensional spectra in selective detection of multiple quantum transition by displacing the phase of a high-frequency pulse by using a rectangular phase detection system to determine a free attenuation signal and subjecting the same to double Fourier transform. CONSTITUTION:A sample coil 2 is provided in the space of a magnet 1. A pulse is then transmitted from a high-frequency oscillator 3 and is made incident on the coil 2 after the phase is changed by a variable phase shifting circuit 4. A pulse is then emitted from the coil 2 and is inputted through a gate 7 to demodulating circuits 9, 10 of a two-channel detecting system. The free attenuation signal from the detecting system is subjected to analog-to-digital conversion 12, 13 and arithmetic operation 14. The phase of the pulse is consecutively changed 90 deg. like 90 deg., 180 deg., 270 deg. to the value phi and is inputted successively. The set of the linear combination is made from the attenuation signal for the prescribed time after the pulse transmission and is subjected to Fourier transform, then the two- dimensional spectra are calculated. The set of the linear combination is made by the phase conversion and therefore the ghost of the two-dimensional spectra is eliminated.
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