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:
Nov. 05, 1996
Filed:
Oct. 04, 1995
Richard W Citta, Oak Park, IL (US);
Larry E Nielsen, Chicago, IL (US);
Zenith Electronics Corporation, Glenview, IL (US);
Abstract
An adaptive equalizer decision circuit for a digital television signal, including a field synchronizing signal, consisting of multilevel symbols and a DC offset representing a pilot. The variation of the DC level of the received signal during the field sync with respect to a predetermined threshold is derived for placing the equalizer in a training signal or data directed operating mode. Another approach determines the difference between a current value of the field sync and each of a plurality of values of the field sync in previous fields and determining therefrom whether the equalizer should be in its data directed mode of operation or in its training signal mode of operation. A modification consists in controlling the step size of the equalizer based upon either the DC level variation or the field sync differences of the received signal. The modification may be used alone or in combination with the equalizer operating mode control.