Importance

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Abstract

A television (TV) monitor or receiver normally displays only the active portion of a video signal, and generally the HBI (horizontal blanking interval) and/or the VBI (vertical blanking interval) are not displayed. In some TV displays however, there is provision to display at least a portion of a blanking interval (overscan area). In some displays (such as monitors for professional use) the VBI is displayed as a way to allow the user to monitor test, command, and/or reference signals. If there are added pulses such as the well known copy protection signals present in blanking intervals of the video signal that cause a horizontal (or vertical) timing or recovery circuit to result in erroneous timing, then viewing is impaired of at least one blanking interval for the TV display. For example, if added copy protection pulses in the VBI region cause the horizontal phase lock loop circuit in a TV display to cause a mistiming, then viewing of signals in the VBI (overscan area) will be impaired. Such signals may include test signals and/or sync signals. A method and apparatus disclosed here improve or correct timing in TV display circuits to allow better viewing of the blanking intervals. One such method is to reposition and/or to remove or modify at least one added or other pulse in the VBI and/or HBI.

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First Claim