NTSC receiver useable with Teletext/Viewdata information Patent #: 4233628
ApplicationNo. 06/257389 filed on 04/24/1981
US Classes:348/556, For format with different aspect ratio348/473, Including additional information348/776Cathode-ray tube image source
ExaminersPrimary: Martin, John C.
Attorney, Agent or Firm
International ClassesH04N 3/22 (20060101)
H04N 5/74 (20060101)
Foreign Application Priority Data1980-04-25 JP
AbstractA variable aspect ratio television receivier, which can receive a non-standard television signal containing an identification signal superimposed upon video signal for the first several horizontal scanning lines in the vertical scanning period. An AND gate is adapted to detect the aforementioned identification signal as such if the signal has a frequency within a range sufficiently higher than to the horizontal scanning frequency and lower than and sufficiently distinguishable from the color sub-carrier frequency, and has a sufficient level within a range conforming to the broadcasting standard continuously for a predetermined period in its predetermined section, and the output of the AND circuit is used to drive a deflection amplitude switch relay circuit for controlling the horizontal deflection amplitude of the image reproduction.