Abstract: A controlling device of a liquid crystal display is provided. The controlling device includes an A/D interface, a sampler, and a shift error correction circuit. An input end of the A/D interface receives an analog video signal for being converted, so as to output a digital video color level. The sampler is coupled between a reference potential and the input end of the A/D interface, and a controlling end of the sampler receives a correction signal. The shift error correction circuit receives the digital video color level, the correction signal, and a target value corresponding to the reference potential. When the correction signal is enabled, the sampler is ON, and the shift error correction circuit performs a correction operation on the received digital video color level and the target value to get a correction value for the A/D interface that corrects the conversion error of the A/D interface.

Abstract: A anti-copy programme signal is provided. Copies of the anti-copy video pulses made on a video recorder experience reduced quality and interference in playback making them unpleasant to watch. The uncopied signal can be viewed without any material effect on picture quality. The signal comprises a pulse added to each line of the signal throughout both the visible picture region and throughout the vertical blanking region, as well as a first modulated wave-form added to the vertical synchronization pulses of the signal and a second modulated wave-form added to several lines of the picture signal before the vertical blanking section. The presence of all three of these features together has been found to provide a surprising accumulative effectiveness in causing interference in the reproduction of the modified video signal during playback of the copied video signal, that is greater than the effectiveness provided by the different features taken separately.