| 摘要 |
PURPOSE:To lower the saturation degree of chrominance components to suppress the color noise in the dark part, by extracting the low-level apart from the luminance signal. CONSTITUTION:The luminance signal applied to terminal 1 is clamped by diode 4. Since the fixed bias is applied to the base of transistor 5, the signal obtained by extracting the low-level part of the luminance signal is obtained in the collector of transistor 3. Meanwhile, chrominance components are applied to terminal 9, and chrominance components where the dark part of the luminance signal are restrained is obtained at terminal 10. Consequently, since the dark part of the luminance signal is restrained, the screen of little noise is obtained even in the weak electric field. |
