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:
Sep. 12, 1989
Filed:
Dec. 08, 1987
Shin-ichi Amemiya, Yokohama, JP;
Kenji Ishiwata, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
An ultrasonic continuous wave blood flowmeter using Doppler effect analysis includes a filter having a cut-off frequency determined in part by a manually selected zero shift value. A tranducing device, in the flowmeter includes a transmission element and a reception element, the transmission element transducing an electric transmission signal into an ultrasonic signal to irradiate a living body and the reception element transducing a reflected ultrasonic signal into an electric reception signal. A detecting circuit is operatively connected to the transducing device for orthogonally detecting the electric reception signal and outputting a Doppler detection signal. A filter circuit is operatively connected to the detecting circuit for cutting high frequency components of the Doppler detection signal based on the cut-off frequency and outputting an analog signal. A converting circuit is operatively connected to the filter circuit for converting the analog signal of the filter circuit to a digital signal based on a Doppler sampling frequency having a continuous wave. A transforming circuit is operatively connected to the converting circuit for analyzing the digital signal and obtaining a Doppler frequency spectrum based on a Fourier transform method. A control circuit is operatively connected to the filter circuit for controlling the cut-off frequency based on the Doppler sampling frequency and the zero shift value.