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:
Jan. 21, 1992
Filed:
Mar. 21, 1991
Dietrich Hassler, Uttenreuth, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
In a method for calculating the flow velocity of, for example a blood stream, ultrasound pulses are repeatedly transmitted into an examination region with a spacing of a pulse repetition time (Tr). An autocorrelation function (Kii) and a cross correlation function (Kiq) in an environment (Tr.+-.1.5 T) around the pulse repetition time (Tr) are formed from the quadrature components (i, q) of echo signals of respectively successive transmission pulses. The shift of the maximum (.DELTA.t) of the correlation functions (Kii, Iiq) relative to the pulse repetition time (Tr) as a result of the velocity of the flow is fixed in a region (Bn) wherein the ambiguous, mean Doppler frequency (.omega.) identified in a traditional way lies. The apparatus for the implementation of this method comprises a shift identification circuit for this purpose. This shift identification circuit calculates the shift of the maximum (.DELTA.t) of one or both correlation functions (Kii, Kiq) relative to the pulse repetition time (Tr).