Title:
ULTRASONIC TRANSMITTER/RECEIVER
Document Type and Number:
Japanese Patent JPH05209781
Kind Code:
A
Abstract:
PURPOSE:To measure propagation time with a high resolution by using a relatively low-speed and low-resolution A/D converter by calculating a true zero- cross point time by interpolation from the waveform data of a plurality of addresses with a tentative zero-cross point address as a center. CONSTITUTION:A propagation time calculation means 10 is constituted of a waveform storage part 11, a zero-cross position detection part 12, and a propagation time operation part 13. The waveform storage part 11 is provided with a timing control circuit 110 which 'venerates a write pulse train which is a rectangular wave pulse train with a certain period and a waveform storage circuit 112 which reads and outputs the waveform data at an arbitrary address in an arbitrary order according to a request from the detection part 12. Then, the detection part 12 stores a tentative zero-cross point at the time of last reception into a zero-cross point storage part 121 and then obtains a tentative zero-cross point based on the last tentative zero-cross point by a tentative zero-cross position detection part 122. Furthermore. interpolation is made using the waveform data at a plurality of addresses by a regression straight line operation part 123, thus enabling a true zero-cross point to be calculated with a high resolution.
Inventors:
KASHIWASE YUTAKA
Application Number:
JP20852492A
Publication Date:
August 20, 1993
Filing Date:
July 13, 1992
Export Citation:
Assignee:
TOKIMEC INC
International Classes:
G01H5/00; G01N29/00; G01N29/44; G01S7/526; G01S15/10; (IPC1-7): G01H5/00; G01N29/18; G01N29/22; G01S7/52
Attorney, Agent or Firm:
Takahashi Isamu