| 摘要 |
An automatic impedance adjuster for an MRI system has an impedance adjusting section, an oscillator, a detector, and a controller. The impedance adjusting section is provided to a probe head, and allows variable adjustment of real and imaginary parts of an impedance of the probe head. The oscillator has a predetermined output impedance, and supplies a signal to the probe head. The detector is connected between the probe head and the oscillator, and outputs detection signals respectively corresponding to real and imaginary parts of the impedance of the probe head. The controller supplies a control signal to the impedance adjusting section in response to the signals corresponding to the real and imaginary parts obtained from the detector, and performs control such that the real and imaginary parts of the impedance of the probe head coincide with a predetermined impedance. The controller executes processing including an initial routine for adjusting the impedance of the probe head to be a value for setting the signal corresponding to the imaginary part to be zero and a matching routine for controlling the impedance of the probe head by using the value set in the initial routine as an initial value, and adjusting the impedance so as to set both the signals respectively corresponding to the real and imaginary parts to be zero.
|
