| 摘要 |
PURPOSE:To improve a focusing precision by reducing the influence of a transient noise by making the rising and falling timing of a gate which controls the passage of a video signal delaying and forwarding than the rising and falling timing of a focus signal detecting circuit. CONSTITUTION:The video signal inputted through a buffer 12 is inputted to a focus signal generating means 2 while a gate 24 is opened, and transmitted through each HPF 231-23n the peak values of high frequency components are extracted by PH circuits 251-25n, and sampled/held by SH circuits 611-61n in a prescribed timing. And also, the high frequency components are integrated by integration circuits 261-26n, and sample/held by SH circuits 621-62n in the prescribed timing. At the time of fetching the data of the circuits 611-61n, a CPU 22 obtains a desired output voltage characteristic by multiplying a coefficient by each SH circuit, and sums the data. On the other hand, the rising timing of the circuits 251-25n and the circuits 261-26n is made delaying than the rising timing of the gate 24, and the falling timing of the circuits 251-25n and circuits 261-26n is made delaying than the rising timing of the gate 24 in a prescribed time, so that the transient noise can be removed. |
