Patent ID: 8085640

Claim:
An adjusting method for recording condition for use with an optical disc device that records data into an optical disc medium by using codes whose shortest run length is 2T and reproduces the recorded data by using the adaptive equalizing procedure and the PRML procedure, comprising a step of generating a first binary bit array by binarizing the reproduced signal waveform reproduced from the optical disc medium in accordance with the PRML procedure; a step of generating a second binary bit array and a third binary bit array which are obtained by shifting the interested edge of the first binary bit array to the left and right, respectively; a step of generating a first, a second and a third target signal waveforms corresponding to the first, second and third binary bit arrays, respectively; a step of calculating a statistical average Δ of extended edge shifts D, wherein the reproduced signal waveform is denoted as W, the target signal waveform as T, the second target signal waveform as L, the third target signal waveform as R, Euclidean distances between W, T, R and L are denoted as ED(a,b) where a, b are ones of W, T, R and L, and evaluation value for the error caused when an edge of interest is shifted leftward is represented by xL and an evaluation value for the error caused when an edge of interest is shifted rightward is represented by xR, an amount of edge shift of an edge of interest is denoted as an extended edge shift D, xL is represented by xL = 1 2 ⁢ ( 1 - ED ⁡ ( L , W ) - ED ⁡ ( T , W ) ED ⁡ ( T , L ) ) xR is represented by xR = 1 2 ⁢ ( 1 - ED ⁡ ( R , W ) - ED ⁡ ( T , W ) ED ⁡ ( T , R ) ) the extended edge shift D is represented by D=(xR−xL)/2; and a step of adjusting the recording condition by using Δ, where Δ is the statistical average of D.