Patent ID: 6141064
Filing Date: 2000-10-31
Classification: H04N

Abstract:
A luminance signal generation apparatus for generating a luminance signal representing RGB input signals, comprising:a. a plurality of input receiving circuits configured to receive RGB input signals;b. a combining circuit coupled to the plurality of input receiving circuits for providing a luminance signal representing the RGB input signals, wherein the RGB input signals and the luminance signal all have a blanking level; andc. a clamping circuit coupled to the combining circuit to receive the luminance signal, to receive a constant reference voltage signal and to the plurality of input receiving circuits for adjusting the blanking level of the RGB input signals according to a difference between a blanking level of the luminance signal and the constant reference voltage signal, wherein the clamping circuit is enabled only during a burst period and further comprises a differential amplifier coupled to receive the luminance signal and to receive the constant reference voltage signal for comparing the luminance signal to the constant reference voltage signal and providing a difference signal representing the difference between the blanking level of the luminance signal and the constant reference voltage signal.