| 摘要 |
PURPOSE:To obtain a relatively stable clock even if S/N deteriorates in a weak electric field range, by obtaining the clock by using a synchronizing pulse at the start position of an information signal. CONSTITUTION:Through burst jumping circuit 101 and AND gate 102, multiple gate signal A is made into gate signal C, which is applied to gate 103 to extract character information signal E from video signal I. Then, signal E is applied to NAND gate 104 together with output G of 8-pulse counter 105 which counts synchronizing pulses F outputted by NAND gate 104. Further, gate signal C and output G are applied to AND gate 107 to obtain pulse signal H. Then, when synchronizing pulse F is supplied to the base of transistor 113 together with pulse signal H, the clock generating means consisting of quartz oscillator 119, etc., generates an output of a frequency phase-locked to synchronizing pulse F. Then, writing to a memory is performed with a write clock. |
