| 摘要 |
PURPOSE:To obtain a picture with least influence of noise by constituting the interlace display circuit of a cathode-ray tube displayer so that a constant current source for superposing vertical deflection currents which is operated by a decision signal representing an odd-number field or an even-number field, is connected with a deflection DC coil to deflect the output of a vertical deflection circuit. CONSTITUTION:The titled system is constituted of an odd/even number field decision circuit 1, the vertical deflection DC current superposition circuit 2 that is driven by a decision signal outputted by the former circuit 1, and a vertical amplitude detection-amplification circuit 5 from which provides such a signal to correct a superposed current to satisfy the vertical size of the screen so that the interlace ratio comes constant even if said size varies. With this constitution, an interlace correction current outputted by the circuit 2 is superposed on a current through the deflection coil during an even number field period or an odd-number field period. Thus either an odd-number field or an even-number field is shifted upward or downward for a length in vertical deflection direction equivalent to half a horizontal scanning period. In such a way, an interlace display can be achieved. |
