METHOD OF CONVERTING A SERIES OF M-BIT INFORMATION WORDS TO A MODULATED SIGNAL, RECORDING DEVICE AND OPTICALLY DETECTABLE TYPE RECORD CARRIER

摘要

A method of converting a series of m-bit information words to a modulated signal is described. For each information word from the series an n-bit code word is delivered. The delivered code words are converted to the modulated signal. The code words are distributed over at least one group (G11, G12) of a first type and at least one group (G2) of a second type. For the delivery of each of the code words belonging to the group (G11, G12) of the first type the associated group establishes a coding state (S1, S4) of the first type. When each of the code words belonging to the group (G2) of the second type is delivered, a coding state (S2, S3) of the second type is established which is determined by an information word belonging to the delivered code word. When one of the code words is assigned to the received information word, this code word is selected from a set (V1, V2, V3, V4) of code words which depends on the coding state (S1, S2, S3, S4). The sets of code words (V2, V3) belonging to the coding states (S1, S2) of the second type are disjunct. The DC and LF parameters of the modulated signal are improved, when in a coding state of the first type (S1 and S4), by assigning a codeword from a set of an other state of the first type, while not violating the dk-constraint. That one of the sets of the first type is selected, of which the codeword results in the best momentary running DC value. The method can be applied to 8 to 15, 8 to 16 (like EFM+) or other codes with coding state mechanisms. Further a record carrier, a signal, a coding and a recording device are disclosed.