| 摘要 |
PURPOSE:To reduce search noises and dropout compensation noises with small- sized, inexpensive circuit constitution and to obtain images of good quality by providing low-band emphasis and high-band suppression characteristics as frequency characteristics at the time of a small signal amplitude. CONSTITUTION:Signals reproduced from a magnetic tape 1 by magnetic heads 21 are amplified by a preamplifier 3 and selected alternately by a switching amplifier 4 and a luminance signal s extracted through an HPF 5. The extracted luminance signal is inputted to an AGC 7 after its high band nearby a carrier is increased by a playback FM equalizing circuit 6. The playback luminance FM signal after the gain control of the AGC 7 is supplied to a HPL 8 to suppress the low-frequency range and emphasize the high-frequency range. A LPF 26 extracts only the low frequency component from the output of the HPL 8. A limiter 27 limits the amplitude when the amplitude is large and amplifies it when small. The output of an adding circuit 28 has low-band emphasis characteristics only when a noise level is small, so the whitening of the noise is suppressed to make the noise visually inconspicuous.
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