A TV analogue to digital conversion system

A two-chip system has been developed to simplify the conversion of analog TV signals into a digital format suitable for storage in a field store used in picture applications or for use in a computer environment. In this type of application, the system clock is usually required to be a discrete multiple of horizontal line frequency, i.e. line locked. The system consists of a bipolar signal processor driving a CMOS triple analog-to-digital converter. An external divider gives the required division ratio between the system clock and the TV horizontal line rate. Signals are accepted in all standard formats, i.e. NTSC/PAL/SECAM composite video, luminance with color difference signals, S-VHS, or RGB. Separate composite sync signals may be used in conjunction with these signals. Measurement results for the A/D converter are given