Recording medium as well as recording apparatus and reproduction apparatus for the same

A reproduction apparatus for reproducing data recorded on a recording medium such that positions of a leading edge and a trailing edge of each of pits formed at predetermined periods are shifted to individually selected ones of predetermined stepwise positions from a respective reference position in accordance with recording data to record the recording data on the recording medium, the thus recorded data being read by sampling a reproduction signal reproduced from the recording medium in synchronism with a sampling clock signal, the recording medium having formed periodically thereon first areas in which the recording data are recorded and second areas in which a reference signal for reading the recording data recorded in the first areas is recorded, the reference signal including a phase reference signal which serves as a reference for fine adjustment of a phase of the sampling clock signal, comprising:

• reproduction means for reproducing the recording medium;
• sampling clock production means for producing the sampling clock signal in response to the reproduction signal reproduced from the recording medium by said reproduction means;
• sampling means for sampling the reproduction signal from the recording medium in response to the sampling clock signal;
• phase adjustment means for finely adjusting a phase of the sampling clock signal in response to the phase reference signal sampled by said sampling means;
• wherein the phase reference signal which includes a signal of a first pattern constituted from positions of three successive first, second and third edges and a signal of a second pattern constituted from positions of successive three other fourth, fifth and sixth edges and complementary to the first pattern is recorded on the recording medium, and said phase adjustment means includes delaying means for delaying the sampling clock signal produced by said sampling clock production means, extraction means for extracting a signal of the first pattern and a signal of the second pattern, which constitute the phase reference signal, from an output of said sampling means, and control signal production means for producing a control signal to control a delaying time of said delaying means from a signal extracted by said extraction means;
• wherein said extraction means includes holding means for holding the output of said sampling means corresponding to the second edge and the fifth edge, and said control signal production means includes subtraction means for calculating a difference between the signals held by said holding means;
• and
• wherein the phase reference signal includes a first phase reference signal for fine adjustment of a phase of a first sampling clock signal for sampling the reproduction signal at the leading edges, and a second phase reference signal for fine adjustment of a phase of a second sampling clock signal for sampling the reproduction signal at the trailing edges, and each of said holding means, said subtraction means and said delaying means is provided by a pair separately for the first phase reference signal and for the second phase reference signal, said sampling clock production means generating the first sampling clock signal at a timing of each trailing edge whereas said sampling clock production means generates the second sampling clock signal at a timing of each leading edge, said delaying means for the first phase reference signal delaying the first sampling clock signal generated at the timing of each trailing edge in accordance with the control signal produced by said holding means and said subtraction means for the first phase reference signal to produce and output the first sampling clock signal for sampling the reproduction signal at the leading edge, said delaying means for the second phase reference signal delaying the second sampling clock signal generated at the timing of each leading edge in accordance with the control signal produced by said holding means and said subtraction means for the second phase reference signal to produce and output the second sampling clock signal for sampling the reproduction signal at the trailing edge.