| 摘要 |
PURPOSE:To obtain a chroma signal of NTSC system by separating first color difference linearly sequential signals and adjusting their levels, thereafter, selectively adding then again to form second color difference linearly sequential signals, then applying balanced modulation to the second color difference linearly sequential signals to synchronize them. CONSTITUTION:Burst flag signals BF are made signals in every other 1H in AND gate 102 by using LINE SW signals that inverts at every 1H, and these signals are added with color difference linearly sequential signals by an adder 101, and thus a signal BF is eliminated form a signal (B-Y). Further, inverted signals are formed from the burst flag signals BF by an inverter 102' and added with each other by an adder 101. A resulting signal is subjected to a clamping circuit 103, and balanced-modulated by a modulator 104. Subcarrier input SC to the modulator 104 i.e. SC-R and SC-B are switched at every 1H by a gate circuit 105 by using a LINE SW signal. Thereafter, a balanced OH signal is delayed by 1H length by a 1H-delay line 106. An OH signal and a 1H signal are added with each other by an adder 107 to form a chroma signal of NTSC system.
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