Optical disk track counting apparatus and method for improved track access

Claim 2

A track-counting apparatus for an optical disk, comprising: an optical detecting head which detects light reflected from an optical disk, a first waveform-generating circuit connected to said head and which detects a tracking-error signal showing a skew of a beam spot from a track, from a playback signal output from said head and generates a track-crossing signal by a binary quantization of said tracking-error signal at a point of zero crossing of said tracking error signal; a second waveform-generating circuit connected to said head and which generates, from said playback signal output from said head, a mirror signal that indicates a mirror-surface area between tracks of said optical disk; and a track counter connected to said second waveform-generating circuit and which counts a number of tracks traversed by a spot beam which strikes a surface of an optical disk, when it is moved in a radial direction of the optical disk, in response to both said track-crossing signal and said mirror signal, and wherein said track counter further comprises: an edge-detection circuit which detects an edge of said track-crossing signal and generates an edge-crossing signal; a logical product circuit which takes a logical product of said edge-crossing signal generated by said edge-detection circuit and said mirror signal, and generates an effective edge signal; and a counter for counting the number of tracks traversed by said spot beam, in response to said effective edge signal wherein said track counter further comprises a seek direction discriminating circuit which determines a seek direction of said head by judging from a target track and a current track position of said head.

Claim 3

A track-counting apparatus for an optical disk, comprising: an optical detecting head which detects light reflected from an optical disk, a first waveform-generating circuit connected to said head and which detects a tracking-error signal showing a skew of a beam spot from a track, from a playback signal output from said head and generates a track-crossing signal by a binary quantization of said tracking-error signal at a point of zero crossing of said tracking error signal; a second waveform-generating circuit connected to said head and which generates, from said playback signal output from said head, a mirror signal that indicates a mirror-surface area between tracks of said optical disk; and a track counter connected to said second waveform-generating circuit and which counts a number of tracks traversed by a spot beam which strikes a surface of an optical disk, when it is moved in a radial direction of the optical disk, in response to both said track-crossing signal and said mirror signal, and wherein said track counter further comprises; an edge-detection circuit which detects an edge of said track-crossing signal and generates an edge-crossing signal; a logical product circuit which takes a logical product of said edge-crossing signal generated by said edge-detection circuit and said mirror signal, and generates an effective edge signal; and a counter for counting the number of tracks traversed by said spot beam, in response to said effective edge signal, wherein said track counter further comprises a seek direction discriminating circuit which determines a seek direction of said head by judging from a target track and a current track position of said head, and wherein said track counter further comprises a direction discriminating circuit connected to said first waveform-generating circuit and said seek direction discriminating circuit and which generates a pulse-discriminating signal from said track-crossing signal in response to an output of said seek direction discriminating circuit.

Claim 4

A track-counting apparatus for an optical disk, comprising: an optical detecting head which detects light reflected from an optical disk, a first waveform-generating circuit connected to said head and which detects a tracking-error signal showing a skew of a beam spot from a track, from a playback signal output from said head and generates a track-crossing signal by a binary quantization of said tracking-error signal at a point of zero crossing of said tracking error signal; a second waveform-generating circuit connected to said head and which generates, from said playback signal output from said head, a mirror signal that indicates a mirror-surface area between tracks of said optical disk; and a track counter connected to said second waveform-generating circuit and which counts a number of tracks traversed by a spot beam which strikes a surface of an optical disk, when it is moved in a radial direction of the optical disk, in response to both said track-crossing signal and said mirror signal, and wherein said track counter further comprises; an edge-detection circuit which detects an edge of said track-crossing signal and generates an edge-crossing signal; a logical product circuit which takes a logical product of said edge-crossing signal generated by said edge-detection circuit and said mirror signal, and generates an effective edge signal; and a counter for counting the number of tracks traversed by said spot beam, in response to said effective edge signal, wherein said track counter further comprises a seek direction discriminating circuit which determines a seek direction of said head by judging from a target track and a current track position of said head, and wherein said track counter further comprises a direction discriminating circuit connected to said first waveform-generating circuit and said seek direction discriminating circuit and which generates a pulse-discriminating signal from said track-crossing signal in response to an output of said seek direction discriminating circuit.

Claim 5

A track-counting apparatus for an optical disk according to claim 2, wherein said track counter further comprises a count pulse separating circuit connected to said logical product circuit and said direction discriminating circuit and which separates said effective edge signal into a count-down signal and count-up signal, in response to said pulse-discriminating signal output from said direction discriminating circuit so as to be supplied to said counter.