| 摘要 |
PURPOSE:To achieve maximum security of image quality of a video signal by conforming the video signal to be inputted to an A/D converter to a dynamic range of the A/D converter by a method wherein a clamp circuit feeds back a DC voltage level of an analog signal to be supplied to an input terminal of the A/D converter. CONSTITUTION:A video signal is demodulated to a luminance signal and two color difference signals with a decoder 1 and is inputted to a pre-treating circuit 3 of an A/D converter. Herein, an input signal is clamped with DC voltage conformed to a dynamic range of A/D converters 41, 42 to be connected to a latter part. When an image is adjusted by using a controller 8, a color selective switch 9 successively switches a signal of color to be printed synchronized with performing specific operation of photographic paper, ink paper, and a thermal head 12 by control of a system controller 13. After being clamped with a pretreatment circuit 3 of the A/D converter, the selected color signal is converted to a digital data with the A/D converter 41. After said digital data is converted to an electrification pulse corresponding to the digital data with a print half tone control circuit 11, a full colored video print image can be obtained on the photographic paper. |
