Tokyo Shibaura Denki Kabushiki Kaisha

Satoshi Sugiura

Hirokazu Suzuki

Mitchio Mitomi

Apparatus is provided in an NMR diagnostic apparatus for reducing or eliminating low frequency cyclic noise. The NMR signals are phase demodulated using reference signals having the same frequency as the excitation signals. A provision is made to change the phases of the output reference signals by 180.degree.. These signals are selectively used to demodulate the received NMR signals which are first divided into two signals of the same phase. The demodulated signals, which are 180.degree. apart, are added thereby eliminating the cyclic noise component.

Nuclear magnetic resonance diagnostic apparatus

In an NMR diagnostic apparatus, it is generally necessary to tune a receiver tuning unit with respect to a patient. The NMR diagnostic apparatus is comprised of a standard signal generator for generating a CW signal, a receiver tuning unit which is mainly constructed by a receiver probe head and a series circuit of a capacitor and a variable capacitance diode and receives the NMR signals induced from the CW signal, quadrature detectors which detect the NMR signals, and a signal processor which processes the detected NMR signals so as to produce the control voltages 'Vc'. The automatic tuning operation is carried out in such a manner that varying the control voltage 'Vc' which is applied to the variable capacitance diode enables the receiver tuning unit to be tuned with respect to the object that is positioned in the receiver probe head.

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Tochigi, Japan

Satoshi Sugiura