METODO DE GRABACION YNO REPRODUCCION DE SENALES DE VIDEO ENCOLORES.

摘要

1,191,692. Colour video recording or reproducing. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 15 May, 1967 [18 May, 1966], No. 22334/67. Heading G5R. A method of recording and reproducing colour video signals on and from a record carrier in tracks each containing at least one kind of information about at leat one field period of a video signal is characterized in that of all the kn2 kinds of field information of kn successive fields, wherein k is a positive integer and n is the number of kinds of information of a colour video signal, kn kinds of field information are recorded in n tracks, the n kinds of information each having a length of at least one field period and always being recorded in the same sequence in these n tracks on the record carrier; during reproduction n reproducing members simultaneously scan the tracks in such manner that each track is scanned n times; the n reproducing members each scan simultaneously a different kind of information of the colour video signal and each scans successively all the kinds of information in cyclic sequence. As shown in Figs. 1 and 2, a recorder tape 1 is helically laid around a drum 2 having a slot 4 provided at right angles to its axis 3 and in which a group 5 of three recording and reproducing members 6, 7 and 8 (relatively spaced by a distance a cosecαin the direction of length of the recorder tape) can rotate.αis the angle made by the tracks 9 with the longitudinal direction of the tape 1 and a is the distance between the centres of the tracks 9, that is, the distance moved by the tape 1 in the direction of the axis 3 after one revolution of the recording and reproducing members 6, 7 and 8. Fig. 2 shows the tracks when k = 1. The group 5 records three tracks, each containing one of the three kinds of information of a colour video signal, e.g. R,G and B associated with the odd field F 1 . During the next two revolutions the recording members 6, 7 and 8 are not energized, but during the fourth revolution they record the even field F1 2 , the tape having moved on a distance 3a during the preceding revolutions. During the scanning process the reproducing members 6, 7 and 8 are continuously switched on and scan successively the tracks: R, G and B of F 1 ; G and B of F 1 and R of F1 2 ; B of F 1 and R and G of F1 2 ; R, G and B of F1 2 ; and so on. Thus, during two of the three revolutions, the reproducing members 6, 7 and 8 scan two kinds of information of an even field and one kind of information of an odd field, or vice versa, so that special steps are necessary (e.g. a delay line) to turn kinds of information of even fields into kinds of information of odd fields, or vice versa. But this difficulty may be overcome by making k even, e.g. 2. In Fig. 4 recorder tape 21 is helically laid in a half turn around a drum 21 and is swept by each of two recording members 26 and 261 through an angle of 180 degrees; the tape moves on over a distance a after half a revolution of the recording members. Where k = 1 and n = 3, tracks as shown in Fig. 6 are produced, the recording members being continuously switched on. During scanning, two groups 25 and 251, Fig. 6, each of three reproducing members 26 to 28 or 261 to 281, simultaneously scan three tracks, e.g. R of F 1 , G of F1 1 and B of F 2 ; G of F1 1 , B of F 2 and R of F1 2 ; and so on.