| 摘要 |
<p>PURPOSE:To make it possible to carry out highly accurate error correction over a transmissible wide horizontal frequency band within the same frame by using an inverting means to invert a clock for A/D conversion for each field, and by forming a DCT block into a diamond shape. CONSTITUTION:A clock to be output from a PLL circuit 12 is supplied to an A/D converter 12a via an inversion control circuit 12d. This inversion control circuit 12d carries out inversion and non-inversion of clock phase based on a field discriminating signal. Accordingly, a transmissible horizontal frequency band by sampling can be extended twice big. Further, digital image data written in frame memory 13a is read in unit of diamond block by one frame of data, and treated block by block in a DCT arithmetic circuit 14 for DCT conversion and adaptive quantization. Accordingly, if a block lacks data, data can be interpolated with data of 4 surrounding blocks, and further, rectangular corners of a diamond block can be interpolated in unit of picture element.</p> |
