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. 10, 1979
Filed:
Dec. 12, 1977
Richard G Merrell, Darien, IL (US);
Zenith Radio Corporation, Glenview, IL (US);
Abstract
A television receiver includes a recognition system identifying the 19th horizontal scanning line of each field of a transmitted television signal for coupling a vertical interval reference (VIR) signal to suitable signal processing circuitry within the receiver. The recognition system includes a timing circuit defining a pair of predetermined timing intervals in each horizontal scanning line during which the logical characteristics of the composite sync signal are sampled and interrogated. A counter is advanced to a preselected state in response to the samples exhibiting a predetermined sequence of logical characteristics occurring during the vertical sync pulse and its associated following equalizing pulse interval. Subsequently, horizontal flyback pulses are counted and the output of the counter is decoded for identifying the 19th horizontal scanning line. A carryover circuit is provided for rendering line 19 identifications for fields during which the predetermined sequence is unsatisfied in accordance with the last line 19 identification corresponding to a satisfaction of the sequence.