Matsushita Electric Industrial Co., Ltd.

Yuzo Yoshimoto

Yasuhiro Nakamura

Yoshinao Tannaka

Ultrasonic wave is emitted into an examined body. A first electric echo signal is generated in response to an echo of the ultrasonic wave. A controllable filter responsive to a control signal serves to extract components of the first electric echo signal which are in a desired frequency band, so that the first electric echo signal is converted into a second electric echo signal. A logarithmic detection device serves to subject the second electric echo signal to logarithmic compression and detection. A signal generator is operative for outputting plural calibration signals having different frequencies and different amplitudes. An input selection device is operative for connecting the signal generator with an input terminal of the filter during a calibration mode of operation. A control device is operative for calculating a corrective value from an output signal of the logarithmic detection device during the calibration mode of operation, and correcting a logarithmic conversion characteristic and an offset of the logarithmic detection device and the control signal to the filter in response to the calculated corrective value during reception of echoes of the ultrasonic wave.

Growing community of inventors

Yokohama, Japan

Yuzo Yoshimoto