JPH0935273A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform highly accurate automatic adjustment of an output of information read out of a disk without being influenced by a variation of a power source voltage. SOLUTION: A signal read out of information of an optical disk 1 by an optical pickup 3 is extracted, amplified and outputted by a variable gain RF amplifier 4. An output of the RF amplifier and a reference voltage which is supplied by a constant voltage source are read out by an A-D converter 5, and a ratio of an A-D conversion value is calculated by a CPU 6 to control an amplification factor of the RF amplifier 4, and automatic adjustment is carried out to obtain a desired output amplitude.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for reading information recorded on an optical disk, a magneto-optical disk or the like.

[0002]

2. Description of the Related Art A disk device for reading data recorded on an optical disk such as a CD or a magneto-optical disk such as a mini-disk capable of recording and reproducing emits a light beam to a track on the recording surface of the disk by an optical pickup. , The reflected light beam is received to read the recorded information.

The optical pickup output of the optical disk device is R
The data is input to the F amplifier, and the RF amplifier extracts, amplifies and outputs the information. The RF amplifier can change the amplification factor from the outside to change the amplitude of the output signal. The output of the RF amplifier is read by the AD converter and sent to the CPU. The CPU controls the amplification factor of the RF amplifier by comparing it with a preset amplitude value, and adjusts the output of the RF amplifier to a preset amplitude value.

[0004]

However, in the above configuration, when the power supply voltage fluctuates, the full-scale range of the AD converter also changes, and therefore, the absolute value of the minimum reading level (1 LSB). Changes. Therefore, there is a problem that the adjustment result is affected by the fluctuation of the power supply voltage, and an error occurs in the amplitude value of the output of the RF amplifier.

The present invention has been made in view of the above problems of the prior art.
It is an object of the present invention to provide an optical disk device that performs highly accurate amplitude adjustment with little error even if the power supply voltage varies.

[0006]

In order to achieve the above object, the optical disk apparatus of the present invention is configured to rotate the disk on which information is recorded on spiral or concentric tracks, and drive information on the disk. An optical pickup for reading, an RF amplifier for extracting information from the signal read by the optical pickup and having an amplification factor controllable by an external signal, a constant voltage source for supplying a reference voltage, and an output of the RF amplifier. An AD converter that reads the amplitude and the reference voltage of the constant voltage source, and a CPU that processes the AD-converted information and controls the amplification factor of the RF amplifier are provided.

[0007]

According to the above configuration, the ratio between the AD conversion value of the output of the RF amplifier and the AD conversion value of the reference voltage of the constant voltage source is calculated, and the amplification factor of the RF amplifier is controlled to automatically obtain the desired output amplitude. adjust.

As described above, even if the power supply voltage varies due to the adjustment method using the voltage of the constant voltage source as the reference voltage,
An amplitude adjustment error caused by the fluctuation is reduced.

[0009]

Embodiments will be described in detail below with reference to the drawings. FIG. 1 shows a schematic configuration of an optical disk device according to an embodiment of the present invention. In FIG. 1, 1
Is an optical disc on which information is recorded on a spiral or concentric track, 2 is a spindle motor for rotationally driving the optical disc 1, 3 is an optical pickup for reading information on the optical disc 1, 4 is an RF amplifier, and is read by the optical pickup 3. It has a variable gain amplifier that can extract information from a signal and change the output amplitude by a signal from the outside. Reference numeral 5 is an AD converter for converting a voltage which is an analog signal into a digital signal, 6 is a CPU, 7 is a control unit for driving and controlling an objective lens of the optical pickup 3, and 8 is a signal processing unit for processing information recorded on a disc. , 9 are constant voltage sources for supplying a reference voltage.

Next, the operation of this embodiment will be described. Information such as music is recorded on the optical disc 1 and is rotationally driven by a spindle motor 2 as a driving means. The optical pickup 3 emits laser light, focuses it on the track of the optical disc 1, and takes in the reflected light. A signal containing various information recorded on the optical disc 1 is contained in the reflected light. The RF amplifier 4 extracts information from the output signal, amplifies and outputs the information, and its amplification factor is variable depending on a signal from the outside.

The signal extracted and amplified by the RF amplifier 4 is
A control signal relating to the positioning of the objective lens for driving and controlling the objective lens in the optical pickup 3 and a signal relating to the original recorded information. A control signal regarding the positioning of the objective lens is output to the control unit 7, a signal regarding the recorded information is output to the signal processing unit 8, and the amplitude information is sent to the AD converter 5.

The signal extracted by the RF amplifier 4 and the voltage of the constant voltage source 9 are input to the AD converter 5, and the AD conversion value of the voltage of the constant voltage source 9 and the AD of the extracted signal of the RF amplifier 4 are input.
The converted value is sent to the CPU 6.

The CPU 6 calculates the ratio between the AD conversion value of the voltage of the constant voltage source 9 and the AD conversion value of the extraction signal of the RF amplifier 4. A desired amplitude of the extracted signal of the RF amplifier 4 is defined in advance by the ratio, and if it does not match the specified value, the amplification factor of the RF amplifier 4 is changed to obtain a preset output signal amplitude.

[0014]

As described above, according to the present invention,
Since the output amplitude of the extraction signal of the RF amplifier is controlled by using the voltage of the constant voltage source as the reference voltage, the amplitude can be adjusted without being affected by the fluctuation of the power supply voltage.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention.

[Explanation of symbols]

1 ... Optical disc, 2 ... Spindle motor, 3 ... Optical pickup, 4 ... RF amplifier, 5 ... AD converter,
6 ... CPU, 7 ... Control part, 8 ... Signal processing part, 9 ... Constant voltage source.

Claims (1)

[Claims] 1. A drive means for rotating a disc on which information is recorded on spiral or concentric tracks.
An optical pickup for reading information on a disc, and an RF amplifier capable of extracting information from a signal read by the optical pickup and controlling an amplification factor by a signal from the outside,
A constant voltage source that supplies a reference voltage, an AD converter that reads the amplitude of the output of the RF amplifier and the reference voltage of the constant voltage source, processes the AD converted information, and controls the amplification factor of the RF amplifier. A CPU is provided, and the ratio between the AD conversion value of the output of the RF amplifier and the AD conversion value of the reference voltage of the constant voltage source is calculated, and the amplification factor of the RF amplifier is controlled to automatically adjust the desired output amplitude. An optical disc characterized in that.