GB1279829A - Colour television signal generators - Google Patents

Abstract

1279829 Television NIPPON COLUMBIA KK 19 Sept 1969 [26 Sept 1968] 46366/69 Heading H4F In colour television cameras wherein a single pick up tube in conjunction with a striped filter produces e.g. red and blue signals, on subcarriers of differing frequency, and a luminance signal not on a subcarrier, the response of the colour signals falls off at the edges of the tube due to a loss in resolution and a consequent reduction in subcarrier amplitude, and the colour balance at the picture edge is incorrect i.e. when the green signal is derived from the red, blue and luminance signals. In the present arrangement, voltage waveform generators control the gains of amplifiers inserted in one or more of the separated colour channels in a cyclic manner at line and frame frequency to counteract the variable response. Fig. 3 (not shown) illustrates a suitable circuit for such an amplifier when placed before an envelope detector, although it is also possible to incorporate such an amplifier after the detector. Colour signals may also be generated by scanning a monochrome photograph recorded by a camera using a suitable striped colour filter.