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:
Apr. 17, 1990
Filed:
Nov. 17, 1988
Hitachi, Ltd., Tokyo, JP;
Abstract
A first phase control loop not including a signal delay part and a second phase control loop including a signal delay part such as an automatic equalizer are formed independently of each other in a demodulator incorporated in a MODEM. The first and second phase control loops are arranged in such a relation that an input to the second phase control loop is not affected by an output of the first phase control loop, so that correction of a frequency offset by the first phase control loop and correction of a frequency jitter by the second phase control loop can be carried out independently of each other. This arrangement facilitates the design of the first and second phase control loops and improves the stability of the phase control system.