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:
Mar. 18, 1997
Filed:
Dec. 28, 1994
Kazuo Ogoro, Tokyo, JP;
NEC Corporation, , JP;
Abstract
A frequency control circuit for a receiver of phase shift keying (PSK) modulated signals comprises intermediate frequency (IF) signal generation circuit for generating an IF signal from a local oscillation signal. A measurement circuit measures the frequency of the IF signal. A detection circuit detects the frequency shift due to the PSK modulation to output a frequency shift signal in response to a first control signal. A control circuit detects that the frequency of the IF signal is converged until the detection circuit can detect the frequency shift due to the PSK modulation. A frequency control circuit further comprises an arithmetic operation circuit for detecting the frequency of the IF signal which can not be affected by the frequency shift due to the PSK modulation, a local oscillation signal generation circuit for outputting a local oscillation frequency signal in accordance with a second control signal, and a compensation circuit for compensating the second control signal in order to converge the frequency of the IF signal on a desired frequency.