| 摘要 |
<p>PURPOSE:To attain high picture quality by using a 3-dimension digital filter to limit the band at recording, expanding a high frequency spectrum and reproducing a picture at the original position at reproduction and then limiting the band. CONSTITUTION:A picture signal is caught in a 3-dimension spectrum space while its time axis space is matched to a 2-dimension picture space. Then the picture signal is digitized and the time axis is corrected and the band limit in the 3-dimension spectrum space is applied in a 3-dimension digital filter 7 at recording and a high frequency spectrum important for improving the picture quality is moved toward the low frequency by a modulator 15 to apply band compression. On the other hand, the high frequency spectrum moved toward the low frequency is expanded by a modulator 18 and reproduced at the original position at reproduction and a 3-dimension digital filter 7 applies the band limit. The digital picture signal processed as above at recording and reproduction is modulated into an analog signal and outputted with a spectrum in matching with the band of the recording and reproduction system. Thus, high picture quality is attained.</p> |
