| 摘要 |
PURPOSE:To prevent generation of jitter on a TV picture due to the leaked interference of a radio wave and a temperature variation, by independently feedback-controlling a reset operation of a binary counting circuit which has been initialized once. CONSTITUTION:Frequency of integer times of horizontal synchronizing frequency generated in a main oscillator 6 is divided by a frequency-divider 8 and is inputted to a binary counting circuit 1. On the other hand, a skipping circuit 10 for initializing is provided, and a set signal of a logical value 1 is applied from an input line 40, by which a logical value ''0'' is provided to an OR gate 9 from its Q' output line 31. Therefore, a horizontal synchronizing negative pulse outputted from a synchronizing signal generator 7 resets the circuit 1 through a gate 9 and 4. Subsequently, when the circuit 1 counts ''1'', an output line 21 becomes a logical value 1 and resets the circuit 10, therefore, the output line 31 becomes a logical value 1, and the gate 9 does not make the subsequent horizontal synchronizing negative pulse pass through. On the other hand, to tge circuit 1, thereafter, a reset signal coinciding with a horizontal scanning period is supplied by a feeding-back circuit through a NAND gate 5. |
