Digital methods for the timing correction of television signals

摘要

Alternatives to the conventional analogue methods of television-signal timing-correction are outlined in which the signal is stored and time-shifted in digital form. In such an alternative system, the timing information is carried by clock signals, and methods of deriving these clock signals both for writing into, and reading from the stores are discussed.nAn experimental digital timing corrector for a video tape machine, controlled by a pilot-tone added to the input signal, has been built and its performance is described;this might be summarized as effecting the complete removal of timing errors at the cost of introducing some chrominance noise.