| 摘要 |
PURPOSE:To attain high-speed synchronous drawing by estimating a zero-cross point from a sampled value differing in code among the sampling outputs of timing signal components. CONSTITUTION:Reference frequency (fo) is divided by divider circuit 1 and then applied through pulse control circuit 2 to divider circuit 3, whose output is also applied as sampling pulse (fs) to sampling circuit 4. On the other hand, a timing signal component of mean frequency (ft) is passed through circuit 4 and timing signal component extraction circuit 5 extracts a timing signal. Here, zero-cross point estimation circuit 6 estimates a zero-cross point through linear approximation using a sampled value differing in code among outputs of circuit 5. As a result, the number of pulses to be shifted is sent from pulse-number setting circuit 7 to pulse control circuit 2, where output pulsed of divider circuit 1 are extracted. In this way, phase synchronization can be carried out at a high speed. |
