A New Technique for Improving the Sharpness of Television Pictures

In conjunction with the CBS color television system a method has been developed for improving the apparent picture definition, called “crispening.” It uses nonlinear circuitry to decrease the apparent rise time of an isolated step input which is applied to a bandwidth limited system. This gives the color television pictures (with the exception of repetitive patterns representing frequencies beyond system cutoff) the appearance of having been transmitted through a system of greater bandwidth. The basic idea is to add to a waveform with a slow transition a second waveform, representing the difference between the desired waveform and the original waveform. — A simple circuit is described which utilizes nonlinear means for reforming the roughly triangular differential of the step signal into a narrower “spike” roughly triangular in shape which is superimposed on the original waveform to obtain a response corresponding to about half the original rise time. Various crispening circuits have been designed for specific applications and will be discussed in more detail.

Print ISSN

0898-042X

Published

1951-10

Content type

Original Research

DOI

10.5594/J06286