| 摘要 |
PURPOSE:To reproduce stably the picture of a character multiplex broadcast by processing digitally the character signal of a received character multiplex broadcast and reading a character data. CONSTITUTION:A composite video signal via a video detecting circuit 3 is given to an A/D converter 12, where the signal is converted into a digital signal and the signal is processed digitally by a digital signal processing section 13, D/A- converted into an analog signal again and given to a video switching circuit 10. On the other hand, the detection of a clock line signal, detection of maximum and minimum value and detection of a framing code or the like are conducted by a video signal memory 14. Succeedingly, a sample value train where the automatic equalization and processing of impulse noise elimination are conducted digitally is given to a character signal separation circuit 17. Then the sample value separated into a binary value is stored in a character signal memory 18 in 1-bit per each sample value. A data is read from the sample train by a sampling circuit 19. The data obtained in this way is processed by a character signal processing circuit 9 and drives a CRT display 11 via the video image switching circuit 10. |
