| 摘要 |
PURPOSE:To obtain a high quality of picture by providing a balanced transmission line to transmit an electrical signal differentially at a main part on a transmission path connecting a vibrator and transmitting/receiving circuits so that noises unavoidably received inside and outside an apparatus are minimized on the transmission path from the vibrator to the receiving circuit. CONSTITUTION:A differential receiving circuit 14 is provided to output an electrical signal which is obtained based on a difference between signals received at terminals and a balanced transmission line 12 is provided to transmit an electrical signal differentially at a main part on a transmission path connecting a vibrator 11 involved and transmitting/receiving circuits 13 and 14. When an ultrasonic wave is transmitted. pulse signals are generated continuously from a pulse signal generating section 16. But a voltage as difference between the electrical signals is applied to cancel DC components. In the reception of the ultrasonic wave, noises of the same phase overlapping a weak received signal from the vibrator on a transmission line are canceled by an in-phase signal the receiving circuit 14. Thus, effect of noises inside and outside the apparatus being received during the reception can be removed with a simple construction to obtain a higher quality of picture. |
