JPH11353701A - Sampling control circuit of disk player - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sampling control circuit suitable for a disk player capable of recording a signal on the disk and also carrying out the reproducing action of the signal recorded on this disk. SOLUTION: This control circuit is constituted of a signal amplifier circuit 9 for a main beam amplifying a signal obtained from a photodetector 6 for the main beam, a signal amplifier circuit 10 for a sub-beam amplifying signals obtained from photodetectors 7, 8 for the sub-beam, a sampling circuit 12 for the main beam outputting a signal outputted from the signal amplifier circuit 9 for the main beam at the specified timing and a sampling circuit 13 for the sub-beam outputting a signal outputted from the signal amplifier circuit 10 for the sub-beam at the specified timing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk player which records a signal on a disk by a light beam emitted from an optical pickup and reproduces a signal recorded on the disk by the light beam. About.

[0002]

2. Description of the Related Art Disk players which read signals recorded on a disk using an optical pickup have become widespread. Recently, in addition to a reproducing function, a light beam emitted from the optical pickup has been used. Disc players configured to record signals on a disc have been commercialized.

A disk used in a disk player capable of performing a signal recording operation has a track meandering with a small amplitude in advance, and the track meandering is formed based on absolute time information. Have been.
Then, the disc player configured to perform such a recording operation detects an absolute time from a signal called a wobble obtained by detecting a meandering of a track recorded on the disc, and detects music or the like. A data signal, which is a recorded signal, is recorded at a predetermined position, and an absolute time is detected from the wobble signal to perform a reproducing operation.

[0004]

The operation of recording a signal on a disk and the operation of reading a signal recorded on the disk are performed by a reading device called an optical pickup. The light beam to be irradiated includes a main beam for performing a signal recording operation and a signal reading operation and a sub-beam for performing a tracking operation for causing the light beam to follow a track.

[0005] Comparing the light intensities of the main beam and the sub-beam, the main beam is about eight times stronger, and therefore an amplifier circuit for amplifying a signal obtained from a photodetector provided for detecting the main beam. The gain of the amplifier circuit for amplifying the signal obtained from the photodetector provided for detecting the sub-beam is increased by a factor of about 4 with respect to the above gain.

[0006] The adjustment operation of the laser output is performed by a sampling operation.
Sample the voltage obtained from the monitor sensor for the peak level of the pulse signal, which is the signal that drives the laser,
The level adjustment during the reproduction operation is configured to be performed by sampling a signal obtained from the photodetector. The level adjustment operation at the time of the reproduction operation is configured to be performed by a signal obtained by sampling a signal obtained from the photodetector. In this state, the focus control operation and the tracking control operation are performed at the same time. Is performed by using a signal sampled at the same time.

Although the focus control operation is performed by the main beam and the tracking control operation is performed by the sub beam, there is a large difference between the intensities of these beams. Therefore, the gain of the amplifier circuit for amplifying these signals is as follows. The difference is made as described above. The characteristic of the amplifier circuit is that the amplification operation becomes slow as the gain increases, and the characteristics at the time of sampling between the main beam and the sub-beam differ greatly.

As the rotational speed of the disk increases, the effect of the difference in the speed of the amplification operation of the amplifier circuit increases, which causes a problem that the signal reading characteristics deteriorate.

An object of the present invention is to provide a sampling control circuit which solves such a problem.

[0010]

According to the present invention, there is provided a main beam photodetector provided in an optical pickup and for receiving reflected light of a main beam from a disk. A sub-beam photodetector for receiving reflected light of the sub-beam from the disc; a main beam signal amplifying circuit for receiving a signal obtained from the main beam photodetector and amplifying the signal; A sub-beam signal amplifying circuit for receiving and amplifying the signal obtained from the device, a main beam sampling circuit for outputting a signal output from the main beam amplifying circuit at a predetermined timing, For sub-beams that output the signal output from the amplifier circuit at a predetermined timing It is more configuration and sampling circuit.

[0011]

FIG. 1 is a block circuit diagram showing an embodiment of a sampling control circuit according to the present invention, and FIG. 2 is a relationship diagram showing a relationship between a beam of an optical pickup and a photodetector.

In FIG. 2, reference numeral 1 denotes a groove called a pre-groove formed on a disk, which is formed in a meandering manner as shown in the drawing, and the meandering is formed based on absolute time information as is well known. ing. Reference numeral 2 denotes a signal track formed between the pre-grooves 1 so that a signal is recorded by a light beam.

Reference numeral 3 denotes a main beam emitted from a laser element constituting an optical pickup (not shown). When a signal recording operation and a reproducing operation are being performed accurately, a signal track 2 as shown in FIG. It is controlled to be located above. Reference numerals 4 and 5 denote a first sub-beam and a second sub-beam formed before and after the main beam 3, respectively. On the pre-groove 1 as shown in FIG. Each is controlled to be located symmetrically.

Reference numeral 6 denotes a main beam photodetector incorporated in the optical pickup and receiving the reflected light of the main beam 3 from the disk, and comprises four detectors as shown. I have. Reference numeral 7 denotes a first sub-beam photodetector which is incorporated in the optical pickup and receives the reflected light of the first sub-beam 4 from the disk, and is constituted by two detectors as shown in the figure. I have. Reference numeral 8 denotes a second sub-beam photodetector that is incorporated in the optical pickup and receives the reflected light of the second sub-beam 5 from the disk, and includes two detectors as illustrated. I have.

As described above, the main beam 3, the first sub beam 4, and the second sub beam 5 are associated with the main beam photo detector 6, the first sub beam photo detector 7, and the second sub beam photo detector 8. Next, a sampling control circuit which is the gist of the present invention will be described with reference to FIG.

In FIG. 1, reference numeral 9 denotes a main beam signal amplifying circuit which receives a signal obtained from the main beam photodetector 6 and amplifies the signal, and 10 denotes the first sub-beam photodetector 7 and A signal amplifying circuit for a sub-beam which receives a signal obtained from the second sub-beam photodetector 8 and amplifies the signal is provided for each operation of a disc player, a signal reading operation and a signal recording operation of an optical pickup. This is a system control circuit that performs a control operation such as a laser output operation.

Reference numeral 12 denotes the main beam signal amplifying circuit 9
Is a main beam sampling circuit that receives a signal amplified by the above and outputs a sampling output signal to the system control circuit 11 during a sampling operation. 13 is a signal amplification circuit 10 for the sub-beam
Is a sub-beam sampling circuit that receives a signal amplified by the above and outputs a sampling output signal to the system control circuit 11 during a sampling operation.

Reference numeral 14 denotes a first sampling time adjusting circuit whose operation is controlled by the system control circuit 11, which functions to adjust the sampling time of the main beam sampling circuit 12. Reference numeral 15 denotes a second device whose operation is controlled by the system control circuit 11.
This is a sampling time adjustment circuit, which has an effect of adjusting the sampling time of the sub-beam sampling circuit 13.

In such a configuration, the operation of setting and adjusting the sampling time of the main beam sampling circuit 12 by the first sampling time adjustment circuit 14 is performed by the system control circuit 11 which outputs a sampling signal output from the main beam sampling circuit 12. This is done by detecting. Similarly, the operation of setting and adjusting the sampling time of the sub-beam sampling circuit 13 by the second sampling time adjustment circuit 15 is performed by the system control circuit 11 detecting a sampling signal output from the sub-beam sampling circuit 13. .

As described above, since the main beam sampling circuit 12 and the sub beam sampling circuit 13 are provided with two independently operating sampling circuits, the main beam signal amplifying circuit 9 and the sub beam signal amplifying circuit 10 Even if there is a time difference in the amplification operation due to the difference in gain, an optimal control signal can be obtained as a signal necessary for performing the focus control operation and the tracking control operation.

When the sampling time adjustment operation is adjusted so that the recording rotation speed and the reproduction rotation speed of the disk are at the highest speed, that is, the adjustment is performed in a state most susceptible to the inappropriate sampling time. Good characteristics can be obtained that match all rotational speeds.

[0022]

According to the present invention, there is provided a main beam signal amplifying circuit which receives a signal obtained from a main beam photodetector which receives reflected light of a main beam from a disk and amplifies the signal, and a sub beam disk. A signal obtained from a sub-beam photodetector receiving reflected light from the sub-beam is input and a sub-beam signal amplifying circuit for amplifying the signal and a signal output from the main-beam amplifying circuit are output at a predetermined timing. A main beam sampling circuit and a sub beam sampling circuit that outputs a signal output from the sub beam amplification circuit at a predetermined timing are provided, and sampling times of the main beam sampling circuit and the sub beam sampling circuit are independently set. Since it can be set, Even if there is a time difference in the amplification operation due to the difference in gain between the beam signal amplification circuit and the sub-beam signal amplification circuit, it is possible to obtain an optimal control signal as a signal necessary for performing the focus control operation and the tracking control operation. I can do it.

Further, according to the present invention, the sampling time can be adjusted independently, so that the sampling time can be improved even if the gain difference between the main beam signal amplifier circuit and the sub beam signal amplifier circuit varies. State can be set.

According to the present invention, the sampling time is adjusted in the state where the recording rotation speed is the fastest, so that the sampling timing for all recording speeds can be set in a favorable state.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing one embodiment of a sampling control circuit of the present invention.

FIG. 2 is a relationship diagram showing a relationship between a beam of an optical pickup and a photodetector.

[Explanation of symbols]

 Reference Signs List 6 photodetector for main beam 7 photodetector for first subbeam 8 photodetector for second subbeam 9 signal amplifier circuit for main beam 10 signal amplifier circuit for subbeam 12 sampling circuit for main beam 13 sampling circuit for subbeam 14 first Sampling time adjustment circuit 15 Second sampling time adjustment circuit

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI H04N 5/781

Claims (3)

[Claims] 1. A signal read operation and a focus control operation from a disk having a track meandering based on absolute time information by a plurality of beams including a main beam and sub-beams formed before and after the main beam. And a disk player configured to perform a signal recording / reproducing operation by an optical pickup configured to perform a tracking control operation, wherein the reflected light from the disk is provided on the optical pickup and the main beam is reflected from the disk. A main beam photodetector, a subbeam photodetector provided on the optical pickup and receiving reflected light of the subbeam from the disc, and a signal obtained from the main beam photodetector. Signal for the main beam A signal amplification circuit, a signal obtained from the sub-beam photodetector and a sub-beam signal amplification circuit for amplifying the signal, and a signal output from the main-beam amplification circuit are output at a predetermined timing. The main beam sampling circuit includes a main beam sampling circuit and a sub beam sampling circuit that outputs a signal output from the sub beam amplification circuit at a predetermined timing. The sampling times of the main beam sampling circuit and the sub beam sampling circuit are independently set. A sampling control circuit for a disc player, wherein the sampling control circuit is set. 2. The sampling control circuit according to claim 1, wherein the sampling time can be adjusted independently. 3. The sampling control circuit according to claim 2, wherein the adjustment of the sampling time is performed in a state where the recording rotation speed of the disk is the fastest.