Mitsubishi Denki Kabushiki Kaisha

Masayuki Ohta

Kihei Ido

Hideaki Kosaka

Masako Yamada

A data conversion method from m bits of data words into n bits of code words in recording or transmission, in which n is larger than m. A number of bit '0' arranged between one bit '1' and a next bit '1' is restricted to at most 4 in a code string of each code word, and a pair of groups of the n bits of code words corresponding to CDSs (code word digital sum) of two codes +1 and -1 are allowed to correspond to the m bits of data words. One of the two codes +1 and -1 is selectively used according to a DSV (digital sum variation) control signal to convert the m bits of data word into the n bits of code word. A pilot signal formation method using the data conversion method for obtaining a tracking error signal in a magnetic recording and reproducing apparatus, and a rotary magnetic head device for use in a magnetic recording and reproducing apparatus are also disclosed.

Data conversion method, pilot signal formation method using the same

A data conversion method, wherein a sequence of first r-bit datawords is divided into groups of x bits where x is the least common multiple of r and m, an arbitrary first dataword selected from x/r groups of first datawords is divided into x/m, an m-bit second dataword is formed by appending r/(x/m)-bit data, obtained by dividing the first dataword into x/m, to the LSB or MSB side of one or other of the non-divided first datawords, and the word-converted m-bit second dataword is converted to an n-bit codeword (m&lt;n).

Data conversion method and apparatus imbedding pilot signal into

The method and apparatus records/reproduces multiple kinds of digital signals having different data amounts per unit time on a recording medium. The multiple kinds of digital signals are organized into a plurality of blocks. At least two of the multiple kinds of digital signals are organized into blocks having different lengths. A synchronizing signal is appended to each of the plurality of blocks. The synchronizing signal identifies a length of each of the plurality of blocks. This method an apparatus increase the recording rate, and is therefore suitable for higher density recording. In reproduction, synchronization protection is performed for variable synchronization periods based on the length of the blocks being reproduced.

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Nagaokakyo, Japan

Masayuki Ohta