Abstract: An electric signal producing system according to the present invention comprises known signal generating means for generating a known signal having a predetermined frequency, adding means for adding the known signal to a reception signal to generate a mixture signal, an A/D converter for converting the mixture signal to digital data, and a computer for controlling the A/D converter to oversample the mixture signal by a frequency of twice or more as large as a predetermined sampling frequency and calculating in accordance with the digital data.

Abstract: A nuclear magnetic resonance image used for detecting the internal state of a substance is obtained through a phenomenon of nuclear magnetic resonance, which is spin resonance of atomic nuclei, by two-dimensionally sampling a nuclear magnetic resonance signal representative of the information of atomic nuclei in a test piece and then changing the two-dimensional data by two-dimensional Fourier transformation. Interpolative extension of the image is achieved without causing any reduction of the resolution by, in execution of such Fourier transformation, zero-filling the data in at least one of the column and row directions in accordance with the extension rate and increasing the number of the two-dimensional data.

Abstract: A method of imaging flowing fluids, such as human blood, using nuclear magnetic resonance whereby an image of high resolution is obtained. First, nuclear spin is excited in a given slice plane of a sample disposed in a magnetostatic field. Then, phase disorder in a direction of a first field gradient due to the first step is compensated for and at least one 180.degree. RF pulse is applied. Next, the nuclear spin is again excited in the slice plane, after which at least first, second and third magnetic field gradients are applied to derive an output signal.

Abstract: A nuclear magnetic resonance imaging method in which the time necessary for forming a two-dimensional image of a single plane of a sample is significantly reduced, making the method applicable for imaging of the human heart or the like. First, nuclear spin is excited in a given volume of a sample disposed in a magnetostatic field. Secondly, first, second and third oblique magnetic fields are applied to the volume. Thirdly, the nuclear spin is rephased under the second magnetic field gradient by applying a 180.degree. pulse. Fourthly, the nuclear spin is phase modulated in the direction of the third magnetic field gradient prior to or following read out of a spin echo signal derived from the rephasing of the spin. Fifthly, the first through fourth steps are repeated, wherein the third magnetic field gradient in each of the repetitions of the fourth step has a constant absolute value and the direction of the third magnetic field gradient alternates.