Method and apparatus of decoding and deciphering a rotated video signal

Abstract

An arrangement for decoding and deciphering signals having been subjected to an encoding of the MAC type and to an enciphering by cyclic permutation at one point of cut, i.e. by cyclic permutation of the assembly of the chrominance and luminance signals C and Y, respectively, from an abscissa a situated in the chrominance signal, by using a sampling frequency f.sub.o, or at two points of cut, i.e. by cyclic permutation independent of the chrominance and luminance signals C and Y, respectively, from abscissa a.sub.c and a.sub.y, respectively, by using a sampling frequency f.sub.o, especially characterized in that upon reception a sampling frequency f.sub.r is used different from f.sub.o and connected with the latter by the relation ##EQU1## p and q being integers, and in that the new address (es) of the point(s) of cut is (are) chosen equal in the first case to the integral value closest to the result a' of the operation, ##EQU2## and in the second case to the integral values closest to the results a'.sub.c and a'.sub.y of the operations ##EQU3## and ##EQU4## Application: Television receiver according to the MAC standard.