Abstract: Methods and apparatus for recording and reproducing coded digital signals typically assign values of a signal to 2 categories which are separately coded, delayed differently, and subsequently recorded. In order to reduce the loss of such values in the cases of damage to the recording to the greatest possible extent, the values of the signals are coded at least twice in parallel and recorded onto several tracks. In one of the recordings, the sequence of values is modified in such a way that even major damage to the recording can be accommodated without producing non-correctable errors.

Abstract: Method and apparatus for transforming a first sequence of digital data and correction words having a first ordering thereof wherein blocks of data and correction words in the first ordering are formed out of the first sequence Data and correction words are selected from the first sequence and are combined in such manner as to form a second sequence with a second ordering. First and second groups of data and correction words are selected out of the second sequence. The first and second groups have one comon word which also belongs in one of the blocks. The data groups have one common word which also belongs in one of the blocks. The data words of the first and second groups are submitted simultaneously to a checking operation. The results of this operation are evaluated to decide if erroneous data words can be corrected. The second sequence of words is corrected using the correction words indicated by the evaluation.

Abstract: There is disclosed a method of digital signal transmission in which, for serially transmitting digital data of N channels, where N may for example be 16, 24 or 32, these data are serially and successively transmitted in groups of M, where M may for example be 2, 3 or 4, with each said group including data of K channels, where K may for example be 8, and in which a preamble with a pattern violating the rule of modulation for data transmission is provided, for example, at the foremost part of each such group, a data validity evaluation bit is added to the data of each such channel, and parity data is also provided to the totality of bits of each such group. A group address may also be provided to each such group for indicating its group number within the M groups.

Abstract: Described is a method for PCM signal recording in which, when single-channel or multichannel PCM signals are recorded so that one-channel PCM signals are recorded in plural recording tracks, the input PCM signals of one channel are correspondingly distributed to the plural recording tracks with at least one word as a unit, and in which the distributed plural signals are subjected to an encoding operation independently of one another and are recorded on the plural recording tracks. In distributing the input PCM signals by word units, word groups consisting of a predetermined number of consecutive words are sequentially distributed to the recording tracks, or plural consecutive words equal in number to the number of recording tracks are distributed to the tracks.