| 摘要 |
PURPOSE:To follow the fluctuation of scanning lines where information are superposed, by providing a circuit or the like which detects only horizontal scanning lines, where a binary additional information signal such as a character signal is superposed, and stores numbers of these scanning lines. CONSTITUTION:Detecting circuits 71-81 are provided which use the output of a level converting circuit 71, which becomes high-level only when the CRI signal exists, and the pulse output of a width 1H obtained from a decoder 64 to detect and store the presence or the absence of the CRI signal every horizontal scanning line in the 10th H-the 20th H. Consequently, the output of an OR circuit 7A which combines outputs of detecting circuits 71-81 becomes high-level only on horizontal scanning lines where the CRI signal exists. A gate pulse obtained by monostable multivibrators 7C and 7D, a flip flop 7F, etc. is gated in a gate 7K by the output of the OR circuit 7A and is applied to a sample hold circuit 4H. Thus, the device follows the fluctuation of horizontal scanning lines where a binary additional information signal is superposed. |
