| 摘要 |
PURPOSE:To improve the transmission efficiency in transmission and S/N in reception by using an ultrasonic probe which has an electrode split into plural, and obtaining the desired impedance of the ultrasonic probe during the transmission and reception. CONSTITUTION:A control circuit 8 supplies the parallel switching command for the probe 1 to a changeover switch 7, and then the probe 1 and changeover switch 7 are so connected that two split probes 1A and 1B are connected in parallel. When the probe 1 is connected in parallel, the impedance of the probe 1 is reduced as far as the internal impedance of a pulse oscillator 9 is small to increase an ultrasonic wave output, improving the transmission efficiency. The series switching command for the probe 1 is supplied to the changeover switch 7 during the reception, and then the probe 1 and changeover switch 7 are so connected that the two split probes are connected in series. When the noise of a preamplifier is larger than the noise generated by the probe 1 itself during the reception, a receive signal voltage is raised by making a series connection to improve the S/N. |
