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:
Jul. 29, 2008
Filed:
Aug. 02, 2004
Cheng-yi Huang, I-Lan Hsien, TW;
Bao-chi Peng, Taipei, TW;
Wei-ting Wang, Taipei, TW;
Realtek Semiconductor Corp., Science Park, HsinChu, TW;
Abstract
A carrier recovery system includes an in-phase mixer for mixing an incoming signal with an in-phase reference signal to produce an in-phase baseband signal; a quadrature-phase mixer for mixing the incoming signal with a quadrature-phase reference signal to produce a quadrature-phase baseband signal; a DC detector for measuring a DC offset of the quadrature-phase baseband signal; and a frequency synthesizer for generating the in-phase reference signal and the quadrature-phase reference signal according to the DC offset measured by the DC detector. The quadrature-phase reference signal is the in-phase reference signal phase-delayed by ninety degrees. The DC offset of the quadrature-phase baseband signal is caused by a pilot tone of the VSB signal for a selected carrier in an Advanced Television Systems Committee (ATSC) digital television (DTV) receiver. By minimizing the DC offset, the carrier recover system locks the quadrature-phase reference signal and the in-phase reference signal to the selected channel.