Patent ID: 6229459
Filing Date: 2001-05-08
Classification: G11B

Abstract:
A data converting method comprising the steps of:converting m-bit input data into an n-bit converted code using a first table having a conversion code group in which the number of consecutive bits ""0"" between bits ""1"" of the conversion code is limited to not less than d and not more than k, the number of consecutive bits ""0"" on a start side of the conversion code is limited to not more than k, and the number of consecutive bits ""0"" on an end side of the conversion code is limited to not more than k2;adaptively inverting a last bit of the converted code obtained in the step of converting m-bit input data;converting the converted code, which is obtained in the step of converting m-bit input data and the step of inverting a last bit, into an NRZI pattern in which an output is inverted for a bit ""1"" of the code and held for a bit ""0"" thereof;cumulating bits ""0"" and ""1"" of the NRZI pattern as ""-1"" and ""+1"", respectively, thereby obtaining a cumulated value; andperforming one of following steps (a), (b) and (c) for a current code in which the number of consecutive bits ""0"" on the end side of the converted code is larger than (k-k1) among converted codes obtained in the step of converting m-bit input data,(a) executing the step of inverting a last bit, when a sum of the number of consecutive bits ""0"" on the end side of the current code and the number of consecutive bits ""0"" on the start side of a next code following the current code exceeds k,(b) inhibiting execution of the step of inverting a last bit, when the number of consecutive bits ""0"" on the start side of the next code is smaller than d, and(c) when neither condition in the step (a) nor condition in the step (b) are satisfied, determining last bits of the converted code obtained in the step of converting m-bit input data, as invertible positions, and controlling execution/nonexecution of the step of inverting a last bit at each invertible position so as to decrease an absolute value of the cumulated value at a next invertible position,.