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. 26, 1985
Filed:
Aug. 10, 1982
Applicant:
Inventor:
Susumu Sasaki, Fujisawa, JP;
Assignee:
Fujitsu Limited, Kawasaki, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04L / ; H04L / ; H03L / ; H03D / ;
U.S. Cl.
CPC ...
329 50 ; 329123 ; 329124 ; 331 12 ; 331 17 ; 331 23 ; 375 52 ; 375 83 ; 375120 ;
Abstract
A carrier recovery circuit for use in a demodulator for a 2.sup.n -phase PSK modulated signal which comprises a phase-locked loop including a voltage-controlled oscillator (7) and an automatic frequency control (AFC) loop for avoiding the false lock phenomenon. The AFC loop is comprised of two differentiating circuits (21, 25), two mixer circuits (22, 26), and a difference circuit (27), and forms a symmetrical structure so as to exclude undesired noise, thereby carrying out a stable AFC operation.