| 摘要 |
PURPOSE:To make it possible to effectively use an ultrasonic distance detecting apparatus, by mounting a transmission and reception control circuit capable of controlling a transmission pulse number, controlling a time interval performing ultrasonic detection and a pulse generating time interval. CONSTITUTION:One bit of the reading exclusive memory 21 of a transmission and reception control circuit 18 is inputted to the clear of a counter 21. One bit (PULSE) is inputted to an ultrasonic transmitter circuit 12 to control ultrasonic transmission and other one bit is inputted to an ultrasonic detect circuit as the level signal (MEASURE) of a measurable time. When a reflected pulse is detected by the ultrasonic detect circuit 17, the content of the counter 21 is latched to a latch circuit 23 by a get signal and a time is determined from an ultrasonic clock number until the detection of the reflected wave. When a pulse number to be generated is changed, the PULSE content of the address of the memory 21 may be altered and the control of a detection time interval is performed by altering the MEASURE value while the pulse generating time interval is performed by altering an address for setting 1 to CLEAR. |
