Digital Separation and Reconstruction of NTSC Signals

Abstract

A new digital method for separation and reconstruction of NTSC color TV signals is described. Digital conversion between an NTSC signal and its baseband component signals is performed at a sampling rate of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(12/5)f_{sc} \simeq 8.59</tex> MHz (f <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sc</inf> : the color subcarrier frequency), which is lower than the conventionally used <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3f_{sc}</tex> or <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4f_{sc}</tex> sampling rate. Since this lowered sampling rate satisfies the Nyquist condition for NTSC signals, the proposed digital method can provide an effective technique for the component coding of NTSC signals. Simulation results have shown that, with this method, no visible picture quality degradations can be observed for either the color bar signal or SMPTE Pictures.