Combed Aperture Equalization for Color Television Cameras

The color and luminance frequency components of the standard NTSC signal are spaced so that band sharing is optimized by interference cancellation using frequency interleaving. The relationship between the color subcarrier and the line scanning rate is such that the chroma sidebands fall into spaces seldom used by the luminance signal. The two types of undesired luminance signals are: (1) low-visibility luminance components resulting from incomplete interference cancellation; and (2) luminance components that are very close in frequency to the chroma sidebands, causing beats or scintillating effects when viewed on the color receiver. This also applies to the noise that may be present with the luminance signal. — The latter problem is the concern of this paper. Unselective aperture equalization can strengthen luminance frequency components and noise in the spectrum that coincide with chroma sidebands. By “combing” the aperture correcting signal, pictures may be enhanced by an amount previously considered impractical without increasing the edge beats or luminance-chroma heterodyning.

Print ISSN

0361-4573

Published

1970-01

Content type

Original Research

DOI

10.5594/J16707