Abstract: Positions of a group of points of code shift including a plurality of points of code shift and present in each code-shift site of a multi-valued FSK code are identified, a point of code shift correction amount including an amount of displacement between a center point of code shift centered among the group of points of code shift in a direction of time axis and each of the points of code shift is calculated based on the identified positions of the points of code shift, and the point of code shift is corrected on a time axis based on the calculated point of code shift correction amount.

Abstract: When recording is carried out in a DVD-RAM, if at least one address mark could have been detected at the header section, after a test light emission for a laser power control is carried out at a GAP section, normal recording is carried out from GUARD1. Herein, if the delay time in the reproduced data would have increased, and if the head of the GAP section has been passed by at the timing when the AM4 is detected in a period during judging whether the fourth AM has been detected or not, it would not be possible to carry out a test light emission normally at the GAP section. In an optical disc recording device of the present invention, when any of the first to third address marks could have been detected, a test light emission is carried out at the GAP section as conventional, and normal recording is carried out from GUARD1 with controlling the laser powers on the basis of that result.

Abstract: There is provided an optical disc device which can evaluate in a short time as to whether an optical disc is recorded with satisfying the standard or not. An optical disc device for measuring a recording deviation amount of data recorded on an optical disc on which physical addresses are previously provided, includes an address detection circuit which detects the physical address and outputs a physical address detection signal, a timer which is operated in synchronization with reproduced data from the optical disc, a recording deviation amount measurement circuit which measures the recording deviation amount of data recorded on the optical disc by using the physical address detection signal and the count value of the timer, a memory which stores the measured recording deviation amount, and a data transfer circuit which transfers the recording deviation amount to the memory.

Abstract: When recording is carried out in a DVD-RAM, if at least one address mark could have been detected at the header section, after a test light emission for a laser power control is carried out at a GAP section, normal recording is carried out from GUARD1. Herein, if the delay time in the reproduced data would have increased, and if the head of the GAP section has been passed by at the timing when the AM4 is detected in a period during judging whether the fourth AM has been detected or not, it would not be possible to carry out a test light emission normally at the GAP section. In an optical disc recording device of the present invention, when any of the first to third address marks could have been detected, a test light emission is carried out at the GAP section as conventional, and normal recording is carried out from GUARD1 with controlling the laser powers on the basis of that result.