Publication Date:
2011-08-16
Description:
Interferometric methods may be considered to include all methods in which the time necessary for a signal to pass through a medium is determined on the basis of the period of oscillation of which the signal consists, while the distance is determined by noting the coincidence between (1) interference between the measured signal and its reflection and ultrasonic interference, or between another signal serving as a reference and electrical interference in the electronic part of the device. In general, all interferometric methods are relatively simple and permit a high degree of accuracy. Theoretically 48 different variations may be distinguished, about 30 of which are capable of practical application. For liquids, where transverse waves do not exist, the number of possible variations is limited to 40, assuming that absolute velocity measurement is desired.
Keywords:
PHYSICS, GENERAL
Type:
The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 15-20
Format:
text
