| 摘要 |
A receiving circuit (10) includes an amplifier (15) which amplifies receiving signals (SP, SN) of a piezoelectric sensor (2), and a plurality of transistors (11a, 11b) or (12a, 12b), which are connected in parallel to between one end of the piezoelectric sensor (2) and one end of the amplifier (15), and are turned on with phase shift when switching is performed to receiving operations. |
