Accession Number : AD0635530

Title :   AN IMAGE-SUPERPOSITION TECHNIQUE FOR MEASURING TIME BETWEEN ULTRASONIC ECHOES.

Descriptive Note : Technical rept.

Corporate Author : ARMY MATERIALS RESEARCH AGENCY WATERTOWN MASS MATERIALS ENGINEERING DIV

Personal Author(s) : MARTIN, Anthony G.

Report Date : MAY 1966

Pagination or Media Count : 17

Abstract : An image-superposition technique has been developed for accurately measuring the time interval between two ultrasonic echoes. The measurement is made by alternately shifting displayed images of the echoes so that the images are superposed. The amount of shifting is controlled by digital circuitry in such a way that the time interval is the inverse of the frequency of a recurrent square wave. This frequency is measured very accurately by a frequency counter. The accuracy of the final results is limited mainly by the properties of the specimen and ultrasonic apparatus, and by the characteristics of ultrasonic pulses. Including the effects of these factors, measurements are accurate to within a few tenths of a percent. (Author)

Descriptors :   (*TIME INTERVAL COUNTERS, *ECHO RANGING), (*ULTRASONIC RADIATION, ECHO RANGING), TEST METHODS, OPTICAL IMAGES, OSCILLOSCOPES, TIMING CIRCUITS, DIGITAL SYSTEMS, FREQUENCY METERS

Subject Categories : Test Facilities, Equipment and Methods
      Acoustic Detection and Detectors
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE