摘要 |
An apparatus for processing data employs a modification of a zero modulation code. The zero modulation code has a waveform that is symmetrical about a zero signal level within narrow defined limits. Each data digit, 1 or 0, is encoded into two NRZI digits. A relaxed run length limitation allows use of a (d,k) code of (1,4), where (d) is the minimum number of 0 digits between 1 digits and (k) is the maximum number of 0 digits between 1 digits, without violating the frequency and charge constraints. Only five charge states and only one bit lookahead is needed in order to encode data in the (1,4) code.
|