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:
Jul. 30, 1991
Filed:
May. 22, 1989
Abstract
An ultrasonic Doppler blood flow detection apparatus of the invention comprises: a transducing circuit for emitting ultrasonic waves at a predetermined interval and for receiving reflected ultrasonic waves from an object in the blood vessel and converting the received signal into an electric echo signal; a frequency-difference signal producing circuit for producing frequency-difference components between the echo signal and first pair of quadrature signals of a frequency f1 in response to the echo signal and the first pair of quadrature signals; first and second Doppler signal detection circuit for detecting first and second Doppler signals of upper and lower sidebands of the frequency f1 from the frequency-difference components in response to second pair of quadrature signals of a frequency f2; and a frequency difference calculation circuit for calculating frequency difference between output signals from the first and second Doppler signal detection circuits. The frequency difference indicates compressed Doppler shift frequency which can detect a higher velocity of blood flow.