Subjective Effects of Differential Gain and Differential Phase Distortions in NTSC Color Television Pictures

John R. Cavanaugh, Anthony M. Lessman

Differential gain (DG) and differential phase (DP) are measures of the variation in the amplitude and phase, respectively, of the chrominance signal with changes in the amplitude of the luminance signal. The effect of DG and DP distortions are to change the color saturations and hue of the transmitted color in an NTSC TV signal. Subjective evaluations of the impairing effects of DG and DP are necessary in order to establish acceptable limits on TV transmission. Subjective tests were designed to obtain the subjective evaluations of different types and magnitudes of DG and DP distortions. The results of these tests indicate that the mean levels of DP which are rated “just perceptible” or better range from approximately 7° to over 18° depending on the type of DP distortion studied. Similarly, the mean levels of DG which were rated “just perceptible” or better range from approximately 2.4 dB to 3.7 dB depending on the type of DG distortion tested.

Print ISSN
Published
1971-08
Content type
Original Research
DOI
10.5594/J05765