Mark detecting circuit for an optical disk

A mark detecting circuit for an optical disk comprising:

• an input terminal for input of a read signal having a first signal component corresponding to the physical shape of the recording region of the optical disk recording medium and a second signal component corresponding to the marks for prescribed information recorded on said recording region;
• a first signal generating circuit that has said read signal as input and generates a first signal containing said first signal component;
• a second signal generating circuit that has said read signal as input and generates a second signal containing said second signal component;
• and a mark detecting circuit generating circuit that compares said first signal and said second signal to generate a mark detecting signal corresponding to said second signal component.

A mark detecting circuit for an optical disk comprising:

• an input terminal for input of a radial push-pull signal having a first signal component corresponding to the physical shape of the recording region of the optical disk recording medium and a second signal component corresponding to the marks for prescribed information recorded on said recording region;
• a first signal generating circuit that generates a first signal tracking the top envelope or bottom envelope of said radial push-pull signal and corresponding to the waveform of said top envelope or bottom envelope;
• a second signal generating circuit that has tracking characteristics that are faster than the tracking characteristics of said first signal generating circuit, and generates a second signal tracking the top envelope or bottom envelope of said radial push-pull signal and corresponding to the waveform of said top envelope or bottom envelope;
• and a mark detecting circuit generating circuit that compares said first signal and said second signal to generate a mark detecting signal corresponding to said second signal component.