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. 15, 1996
Filed:
Mar. 27, 1995
Yang-seok Choi, Seoul, KR;
Samsung Electronics Co., Ltd., Kyungki-do, KR;
Abstract
An automatic frequency control apparatus used in an MPSK communication system detects a frequency offset between a carrier and a local oscillation signal for adjustment of a local oscillation frequency. A phase difference detector generates a first phase difference detection signal having, as a phase value, a difference between the phases of various samples of the sampled signal. A phase altering unit generates a second phase difference detection signal having a phase value different from that of the first phase difference detection signal. A frequency offset signal generator estimates transmission phase information by using the phase value of the second phase difference detection signal and reference phase signals used for MPSK modulation, thereby generating a frequency offset signal which is determined by the transmission phase signal and the second phase difference detection signal. The result is that the number of the reference phases which are used for determination of the transmission phase information by altering the phase of the phase difference signal, is reduced. Accordingly, the hardware cost for implementing the apparatus can be lowered. The invention can be used for automatic frequency control in a modem which is used for all the types of MPSK modulation.