How to decode the 16/17 ENDEC and 17-bit codeword for decoding a 17-bit codeword into a 16-bit data words into 16-bit data word

摘要

PROBLEM TO BE SOLVED: To provide an encoder/decoder(ENDEC) whose execution is not complicated and which can prevent an error in a decoding output from being propagated. ;SOLUTION: An encoder uses an identical mapping circuit so as to code the high-order byte and the low-order byte of an input data word. Without using a 1/(1+D²) precoder or an NRZ modulator in conventional cases, a data symbol b(n) 8 uses an NRZI modulator 172 so as to be written directly into a magnetic disk 18. A bit '1' inside the data symbol toggles a write current to a negative value from a positive value (or inversely) by using the modulator 172, and a bit '0' does not change a write current. When it is received, first 8 bits are decoded independently of last 8 bits so as to prevent their erroneous propagation. That is to say, the first 8 bits in a code word are decoded into a high-order byte in the decoded data word, and the last 8 bits are decoded into a low-order byte in the same manner, and both are decoded independently of each other.;COPYRIGHT: (C)1998,JPO