| 摘要 |
PURPOSE:To decrease errors in measured values by transmitting the next pulse in synchronization with the receiving of the reflected or transmitted wave from a target object at every receiving of said wave and repeating such operations plural times, thereby making the count time of clock pulses longer. CONSTITUTION:In synchronization with the transmission indicating pulse D inputted from a synchronizing device 9, an oscillator 7 applies a spike-like electric pulse A to a probe 1. An extractor 8 extracts the ultrasonic wave pulses within the prescribed time after lapse of a specified time from the transmission among the ultrasonic wave signals B transmitted by the probe 1 and outputs only the predetermined pulse among these pulses as a signal C. In the device 9, the transmission indicating pulse D synchronized with the signal C is outputted to the device 7. The pulse D outputted first as a signal E and the pulse signal C after outputting of the k-th time of the transmission indicating pulse as a signal F are outputted respectively to a counter 10, where the number of the clock pulses of a period DELTAT is counted. Thereafter, the distance between the probe and the object is calculated in a distance calculator 11. |
