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:
Oct. 12, 1999
Filed:
Mar. 12, 1997
Masaharu Tanai, Tokyo, JP;
Ando Electric Co., Ltd., Tokyo, JP;
Abstract
A frequency deviation measuring device is used in fields of digital mobile communication systems to measure frequency deviations with respect to .pi./4 QPSK modulation signals in accordance with the phase locus method. A center frequency is detected on the basis of a spectrum distribution measured with respect to a testing signal which corresponds to a digital modulation signal. A non-modulation signal is generated based on the center frequency detected from the testing signal. Quasi-synchronization wave detection is performed on the testing signal and non-modulation signal to produce an IQ base band signal. A first frequency deviation is detected based on the IQ base band signal in accordance with the phase locus method. A second frequency deviation is detected based on a difference between the center frequency and a testing frequency set value. The first and second frequency deviations are added together to provide a measured value of a frequency deviation between the testing signal and testing frequency set value. Because the quasi-synchronization wave detection is performed using the non-modulation signal based on the center frequency which is detected based on the spectrum distribution of the testing signal, it is possible to increase a range of measurement for the frequency deviation up to 1/5 or more of the symbol rate.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile