Patent ID: 7245126

Claim:
In an NMR apparatus comprising: means for subjecting a sample or specimen to a strong static magnetic field to induce precessional motion to the magnetic moments of atomic nuclei within the sample or specimen; an RF irradiation coil for applying RF power perpendicularly to the direction of the static magnetic field and at a frequency to induce precessional motion of the magnetic moments in an excited state; first RF power application means for during periods of time applying RF power of a frequency necessary for measurement of an NMR signal to the irradiation; and second RF power application means for, during periods complementary to the period the first power application means is active, applying RF power of a frequency not affecting the measurement of the NMR signal to the RF irradiation coil, wherein the total amount of RF power applied to the detection coil or the RF irradiation coil is controlled to be almost constant irrespective of whether the RF power of the frequency necessary for the measurement of the NMR signal is applied or not, and wherein there is further provided control means for controlling first and second RF power application means such that the sum of the RF power applied to the detection coil or the RF irradiation coil from said first RF power application means and the RF power applied to the detection coil or the RF irradiation coil from said second RF power application means is kept almost constant.