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:
Mar. 09, 2004
Filed:
Feb. 27, 2002
Hitachi Ltd., Tokyo, JP;
Abstract
From a transmitter ( ) and a transmission antenna ( ), a first frequency signal having a fixed frequency is transmitted for a predetermined time or more, a second frequency signal having a certain frequency difference from the first frequency signal is transmitted for a predetermined time or more, and a third frequency signal having a frequency difference twice the frequency distance from the first frequency signal is transmitted for a predetermined time or more. Reflected waves from objects under measurement at the respective transmission frequencies are supplied to a reception antenna ( ), a mixer ( ), an analog circuit unit ( ), an A/D converter ( ), an FFT ( ) and a signal processing unit ( ). Then, the Doppler frequencies are measured for the reflected waves, objects under measurement are separated and detected at each Doppler frequency, and objects under measurements having the same Doppler frequency are separated to identify a plurality of objects under measurement from phase information and amplitude information of received signals acquired at each transmission frequency. In this manner, when there are a plurality of objects under measurement which are substantially equal in relative speed, these can be separated from each other and detected.