The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 21, 1988
Filed:
Jan. 22, 1987
Kageyoshi Katakura, Tokyo, JP;
Toshio Ogawa, Tokyo, JP;
Ishikawa Shizuo, Kanagawa, JP;
Hisashi Nishiyama, Tokyo, JP;
Mashio Kodama, Tokyo, JP;
Hitachi Medical Corp., both of, JP;
Hitachi Ltd., both of, JP;
Abstract
A phase difference comparison type of ultrasonic velocity meter repeatingly transmitting acoustic waves in the form of pulses at alternate time intervals: T-T.sub.S and T+T.sub.S, receiving reflected waves generated by the transmission of these waves and reflected on an object, forming first and second mixed waves by mixing the reception signal obtained from the reflected waves with two reference waves having phases shifted 90 degrees from each other, detecting the phase difference between the present vectors representing the first and second mixed waves and similar vectors which have been obtained with respect to the preceding pulse transmission, detecting the phase difference Q between the phase difference caused in relation to the time interval T-T.sub.S and the phase difference caused in relation to the time interval T+T.sub.S with respect to a phase difference obtained each time a pulse is transmitted, and calculating the Droppler shift angle frequency .omega.d from .omega.d=Q/2T.sub.S.