| 摘要 |
<p>41 In video equipment for recording a colour video signal on a magnetic tape a transmission method is now proposed which will be denoted "colour shift" method. Therein the composite colour video signal which is formed by a sequence of analogue line signals is sampled, as a result of which each analogue line signal is converted into a time-discrete line signal formed by a plurality of line signal samples occurring at a rate fs,each sample being formed by the sum of a luminance and a chrominance signal sample. These time-discrete line signal are submitted to a scrambling operation in which, in accordance with a predetermined pattern, a number of line signal samples is selected from the line signal samples of a group of time-discrete line signals for assembling time-discrete auxiliary line signals. This selection is effected such that of all those line signal samples which together represent a given time-discrete auxiliary line signal the associated chrominance signal samples all have the same polarities. As a result, the chrominance signal is converted without bandwidth limitation to lower frequency band, while it continues to be located within the frequency band occupied by the luminance signal. This new composite color video signal can now, after having been converted into an analogue signal, be transposed in its totality to a suitable transmission band by means of frequency modulation.</p> |
