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. 02, 1987
Filed:
Apr. 18, 1984
Hiroshige Fukuhara, Yokosuka, JP;
Nissan Motor Company, Ltd., Kanawaga, JP;
Abstract
An automatic Loran-C signal detecting apparatus samples a received signal at a constant high sampling frequency of which the Loran-C carrier frequency is a harmonic. The polarity of the sampled signal at each sampling frequency cycle is stored in a corresponding memory cell for every two successive periods of the Loran-C signal. All of memory cells are previously loaded with a value m. A control unit determines whether the polarity of the sampled signal is positive or negative and adds +1 to the value m of the memory cell when the sampled signal is positive and adds -1 to the value m of the memory cell when the sampled signal is non-positive. After a given number of Loran-C signal cycles, the accumulated polarity totals are compared to a range around the original value m to detect which memory cells, i.e. which sampling times, coincide with Loran-C pulses. The polarity of the Loran-C pulses thus detected can then be checked to identify the sending station of each group of Loran-C pulses.