PURPOSE: To improve largely an S-N ratio of a color signal by compressing logarithmically a level by using a recording NR circuit following the color signal at a high speed and by stretching logarithmically the level by using a reproducing NR circuit.
CONSTITUTION: A recording noise reduction circuit NR17 is provided between a low band conversion circuit and adder 5. A reproducing noise reduction circuit 18 is provided between an LPF15 and high band conversion circuit 16. During recording, an input signal enters a differential amplifier 19 whose gain is large enough, passing through a switch 20, separating into two; one enters a VCA21 and the other enters a level detector 22. The detector 22 outputs DC voltage in correspondence with the level. Output of the VCA21 is fed back at the amplifier 19. During reproducing, the switch 20 is connected to the reproduction side to input a signal into the switch 20. As a result, the level of the color signal is compressed logarithmically during recording, and stretched logarithmically during reproducing.
FUKUSHIMA ISAO
KOTANI KAZUYOSHI
KANOU KENJI
| JPS58166896A | 1983-10-03 | |||
| JPS5583352A | 1980-06-23 | |||
| JPS561684A | 1981-01-09 |