Time base corrector

Abstract

A video time base corrector includes an analogue-to-digital converter for converting an incoming analogue video signal to digital form, and a store for receiving successive lines of video information in digital form from the converter. A digital-to-analogue converter converts the digital output signal from the store into analogue form. Control means are provided for writing-in and reading out the digital information into and from the store. A triggered voltage controlled input oscillator determines the rate of conversion of the analogue signal to digital form and the rate of writing into the store. An output oscillator controls the rate of reading out of the digital information from the store and the rate of conversion into analogue form. Sampling means sample the input oscillator controlling voltage during one line and measuring means detect any voltage difference in the controlling voltage during successive lines. Holding means retain the detected voltage difference between successive lines and this is applied to phase shifter means for shifting the phase of the output oscillator in dependance on the voltage difference held by the holding means.

Dependencies are inferred from the claim text.