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:
Feb. 26, 1991
Filed:
Sep. 27, 1989
Hitachi, Ltd., Tokyo, JP;
Abstract
In a pulse Doppler flow speed meter in which ultrasonic wave pulses are transmitted repetitively at transmission intervals T and thereafter transmitted repetitively at transmission intervals (T+Ts), phases of reflected waves due to reflection of individual transmission pulses are measured sequentially to provide phase signals and the phase signals are subjected to frequency analysis to determine speed distributions, distributions of phase differences between phase signals corresponding to transmission pulses transmitted at the transmission intervals T and distributions of phase differences between phase signals corresponding to transmission pulses transmitted at the transmission intervals (T+Ts) are determined. A value of center of gravity of the former phase difference distributions and a value of center of gravity of the latter phase difference distributions are determined and then a phase difference between the two values of center of gravity is determined. Obtained from the phase difference are values of Doppler shift angle, according to which the former and latter phase difference distributions are shifted so as to be compensated for their aliasing.