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. 01, 1996
Filed:
Jul. 31, 1995
Akihiko Matsuoka, Yokohama, JP;
Masayuki Orihashi, Ichikawa, JP;
Kenichi Takahashi, Kawasaki, JP;
Hiroshi Ohnishi, Tokyo, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An automatic frequency compensation apparatus comprises: a frequency offset prediction portion for predicting a frequency offset of an oscillation signal used for receiving a TDM digital modulation signal from the center frequency of the TDM digital modulation signal using a quadrature baseband signal derived from the TDM digital modulation signal, a vector correlation portion detecting a correlation between the quadrature baseband signal and a predetermined signal, the frequency offset prediction portion predicting when the correlation exceeds a reference value, and a frequency offset compensation portion effects a frequency offset compensation to the quadrature baseband. A convergent coefficient may be decreased with the number of events that the correlation exceeds the reference value. An equalizer may be further provided after the frequency offset compensation portion and the prediction is made using the output of the equalizer. The prediction is effected during the training period or during the training period when the correlation exceeds the reference value. The correlation may be detected using the output of the equalizer and a signal obtained by Judging or digitizing the output of the equalizer.