| 摘要 |
PURPOSE:To prevent a reversing phenomenon which keeping an S/N and a frequency characteristic optimum by preventing the reversing phenomenon by an FM equalizer and correcting the deteriorated S/N and the frequency characteristic by a deemphasis. CONSTITUTION:When a modulating characteristic becomes large, a sideband wave becomes large, operates to lower the modulating characteristic and a reversing phenomenon is scarcely generated. An FM signal changing in this manner passes through a limitter 6 and is modulated by an FM modulator 7 and inputted to a deemphasis 8. When the characteristic of an FM equalizer 5 is changed so as to limit the sideband wave of the FM signal having the large modulating characteristic and easily producing the reversing phenomenon, the S/N of the demodulated video signal becomes better and the frequency characteristic becomes worse, so that the characteristic of the deemphasis 8 is changed correspondingly to the change of the characteristic of the FM equalizer 5.
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