Teletext decoder apparatus including feature of inhibiting generation of an end-of-page signal
AssigneeU.S. Philips Corporation
InventorsJohn R. Kinghorn, Jeremy R. Stevens
Life of this patent
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Abstract
A "correct page header received" (CPHR) flip-flop (3) is set by the page header of a required teletext page and reset by the next following page header, a "page end" flip-flop (15) generates a page end output (17) in response to the receipt of the next following page header, a "row received" flip-flop (11) detects at least one row of the required teletext page, a gate (14) inhibits the generation of an end of page output (21) for a predetermined period, typically corresponding to three field intervals, and an AND gate (18) further inhibits the generation of an end of page output (21) if there has been a subsequent detection of a further page header of the required teletext page within the predetermined period.
Claims14
A teletext decoder comprising:
- means for detecting the page header of a required teletext page, means for detecting the next following page header, and means responsive to the detection of said next following page header for generating an end of page signal, means for detecting at least one row of said required teletext page, and means for inhibiting the generation of said end of page signal if 1) at least one row of said required teletext page has not been detected, or 2) there has been a subsequent detection of a further page header of said required teletext page within a predetermined period.
A method of operating a teletext decoder comprising the steps of detecting the page header of a required teletext page, detecting the next following page header, generating an end of page signal in response to the detection of said next following page header, detecting at least one row of said required teletext page, and inhibiting the generation of said end of page signal if at least one row of said required teletext page has not been detected, or if there has been a subsequent detection of a further page header of said required teletext page within a predetermined period.
Dependencies are inferred from the claim text.