DEVICE AND METHOD FOR CONVERTING SCANNING

摘要

An input image signal is converted into a digital form in an A/D converter 6 by clock pulses 53 from VCO 4 of a PLL circuit 1. The frequency of the clock pulses 53 is fixed. After the number of scanning lines is converted in a primary processing circuit 7, the digital image signal is written in field memory 10. The image signal is read out from the field memory 10 by second clock pulses 63 generated in a PLL circuit 11. A frequency divider 15 in the PLL circuit 11 is changed in frequency division ratio by a control signal. As a result, the sampling number in one horizontal period of the image signal read out from the field memory 10 is changed. Since the number of pixels in the effective image period of the image signal written in the memory is constant, by changing the sampling number in one horizontal period on the read-out side, the ratio of the effective image period relative to one horizontal period can be changed to adjust the horizontal size.