| 摘要 |
PURPOSE:To apply low speed processing to a high definition television signal including a broad band signal by separating a high frequency component of a luminance signal at the transmission side while keeping the analog signal and shifting the frequency to a low frequency so as to convert the signal into a digital signal. CONSTITUTION:R, G, B signals from a camera are converted into a Y signal by a signal converting circuit 29 and a high frequency component YH is extracted from an HPF30. The component YH is applied to an A/D converter 36 via a modulator 31 and an LPF32 and converted into a digital signal YH'. On the other hand, the R, G, B signals are fed to A/D converters 37, 38, 39 through LPFs 33, 34, 35 and converted into a digital signal. The digitized R, G, B signals are converted into YL, I, Q signals by an RGB-YIQ converting circuit 40, becomes an NTSC signal at a color encoder 11 and synthesized with the high frequency luminance component YH'. Then the analog transmission signal is obtained via a D/A converter 12 and an LPF13.
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