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:
Jun. 08, 2004
Filed:
May. 13, 2003
Kazuto Nakamura, Hitachinaka, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A diplex Doppler type radar system which can detect a preceding vehicle even when the range rate (e.g. a relative velocity, a relative distance) of a preceding vehicle relative to a vehicle having the radar system is small. A Radar system is mounted on a vehicle, the transmit antenna alternately transmits two signals on different frequencies. When the transmitted signals met an object (a preceding vehicle) and reflected, the reflected signals are received by a receive antenna. Usually, The first A/D converter digitizes IF signals (said received signals) and the DSP (digital signal processor) frequency-analyzes the digitized signals to compute the range rate of the preceding vehicle. When a peak spectrum exists in a low frequency range below a preset threshold as the result of the frequency analysis, the IF signals are digitized by the second A/D converter which has a higher sampling resolution than that of the second A/D converter. The digitized IF signals are frequency-analyzed by the system control microcomputer . Thus the range rate (e.g. a relative velocity and a relative distance between the preceding vehicle and the following vehicle) of the preceding vehicle is computed.