KR19990065927A - Channel integration device for multimedia devices and media playback method - Google Patents

Abstract

The present invention relates to an optical pickup servo apparatus, comprising: an optical pickup (10) for condensing light on a CD signal recording surface and detecting a light reflected by a pit to generate a focusing error signal; An A / D converter 20 for converting and outputting an analog error signal output from the optical pickup 10 into a 16-bit digital signal; A digital filter (30) for filtering low- and high-pass compensation of the signal digitally converted by the A / D converter (20); An adder 40 for adding and outputting a signal output from the digital filter 30 and a separate signal input independently; Cutting means (50) for cutting and outputting the lower 8-bit value of the output signal; A delay unit (60) for delaying the lower 8-bit value cut by the cutting means (50) by one sample and then outputting it to the adder (40); An optical pickup driver (70) for outputting a driving signal for controlling the position of the optical pickup (10) based on the lower 8-bit value cut out by the cutting means (50); A switch 110 provided between the delay unit 60 and the adder 40; And a level detection unit (100) for controlling whether the switch (110) is shorted based on the level size change amount between successive digital data output from the A / D converter (20). If the level of the signal is ideally large in deviation, it is not usefully reflected in the servo control temporarily, so that the optical pickup can be controlled more accurately.

Description

Optical Pickup Servo

The present invention relates to an optical pickup servo device, and more particularly, a feedback value of a servo error signal such as a focusing error signal or a tracking error signal is fed back to a current value to be reflected in the present value. The present invention relates to an optical pickup servo device that temporarily implements a feedback, thereby enabling to realize an accurate servo regardless of a situation.

In an optical disc, data is generally recorded by a pit continuously formed in a spiral shape from the inner circumference to the circumferential direction of the optical disc. In order to accurately read such data, an optical pickup, which is a signal reading means, is precisely separated from the pit. You must move along the correct path while maintaining the.

The role of the optical pickup servo is to precisely adjust the focus of the beam scanned from the optical pickup to the predetermined pit row during reproduction of the optical disc, thereby maintaining a higher reading accuracy of the recorded data. And a focusing servo that maintains a constant distance between the optical disk surface and a tracking servo that causes the optical pickup to move accurately along the path of the pit row.

A compact disc (CD) player, which is a type of optical disc reproducing apparatus, provides light to a signal recording surface of a CD rotated by a motor M, as shown in FIG. An optical pickup 10 for condensing and detecting light reflected by the pit to generate a focusing error signal; An A / D converter 20 for converting and outputting an analog focusing error signal output from the optical pickup 10 into a 16-bit digital signal; A digital filter (30) for performing low-pass compensation and high-pass compensation on the signal digitally converted by the A / D converter (20); An adder 40 for adding and outputting a signal output from the digital filter 30 and a separate signal input independently from the signal; Cutting means (50) for cutting and outputting the lower 8-bit value of the signal output from the adder (40); A delay unit (60) for delaying the lower 8-bit value cut by the cutting means (50) by one sample and then outputting it to the adder (40); And an optical pickup for outputting a driving signal for controlling the position of the optical pickup 10 in a direction of reducing focusing error based on the lower 8-bit value cut out by the cutting means 50 and remaining upper 8-bit value. The drive unit 70; was configured to include.

In the conventional optical pickup servo device configured as described above, an analog focusing error signal generated due to the surface shake phenomenon caused by the rotation of the CD is detected from the optical pickup 10 and is performed by the A / D converter 20. After conversion into 16-bit digital data, the digital filter 30 is inputted to the adder 40 through a low pass compensation and a high pass compensation filtering process.

The adder 40 is also inputted after the lower 8-bit value of the immediately preceding digital data cut by the cutting means 50 after the above process is delayed by one sample by the delay unit 60. In 40), the lower 8-bit value of the immediately read data value is summed and output to the 16-bit data value currently read by the optical pickup 10.

As a result, the lower 8-bit value, which was not used as data data for servo control of the optical pickup 10 as it was cut by the cutting means 50 among the values of the immediately read digital data, is reflected in the next signal. Therefore, the output value from the adder 40 is a value reflecting the immediately preceding data value, not the actual data value that is currently read.

The lower 8 bits are cut back by the cutting means 50, and the lower 8 bits are cut back into the delay means 60, and only the upper 8 bits of the cut value are cut and remain. After inputting), a negative voltage value is applied to the motor 10 to reduce a focusing error, and a positive voltage value is applied to the motor 10 to increase a focusing error. By performing a closed loop operation, the focusing servo of the optical pickup 10 is performed.

In this case, the data value actually input to the optical pickup driver 70 is a value cut from 16-bit data reflecting the lower 8-bit value that was immediately cut off, although only the upper 8-bit is reflected, and thus does not reflect the previous data value. Compared to the actual data can be accurately reflected.

However, the conventional optical pickup servo system configured and operated as described above uniformly cuts the lower 8-bit value of the previous data regardless of whether the signal read by the optical pickup 10 is stable or not, and then uses the entire data of the next data. Since the value is reflected in the value, even when the level of the signal read out by an abnormal situation such as an unexpected disturbance is ideally large, the error of this focusing error signal is reflected in the next signal, thereby failing to obtain an accurate control value. There was this.

Therefore, the present invention was created to solve the above problems, and when the level of the signal read out from the optical disc is abnormally large, the optical pickup can be more accurately controlled by temporarily not reflecting it in the servo control. An object of the present invention is to provide an optical pickup servo device.

1 is a block diagram showing the configuration of an optical pickup servo device according to the present invention;

2 is a block diagram showing the configuration of a conventional optical pickup servo device.

※ Explanation of code for main part of drawing

10: optical pickup 20: A / D converter

30: digital filter 40: adder

50: cutting means 60: delay unit

70: optical pickup drive unit 100: level detection unit

110: switch

An optical pickup servo apparatus according to the present invention for achieving the above object comprises: data separation means for cutting out a lower value of a predetermined unit or less from input digital data; Delay means for delaying the cut out lower value by a predetermined time; Adding means for adding the delayed lower value and the value of the currently read digital data to output the data to the data separating means; And driving means for controlling a reading position of the optical pickup based on the digital data value of which the lower value is cut by the data separating means, the amount of change in the level size of the read digital data. Level change amount detecting means for detecting a; And switching means for disconnecting the lower value from being input into the adding means when detecting the level change amount by a predetermined magnitude or more by the level change amount detecting means.

In the optical pickup servo device according to the present invention configured as described above, the lower value of the immediately preceding data cut by the data separating means is delayed by the delay means for a predetermined time, and then inputted to the adding means to the data value to be read out. After the reflection, the driving means performs a more precise servo control by outputting a driving signal for optical pickup control based on the reflected value.

During this process, the level change amount detecting means continuously detects the amount of change in the level size of the read digital data, and when the detected level change amount becomes more than a predetermined value, the lower level cut by the data separating means is controlled. The value is not input to the adding means. In such an abnormal situation in which the magnitude of the level changes suddenly, the previous data is not reflected in the current data, thereby preventing the servo control from increasing the error.

Hereinafter, the configuration and operation of a preferred embodiment of the optical pickup servo device according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing an optical pickup servo device according to the present invention, wherein the optical pickup servo device according to the present invention performs the same operation as the conventional optical pickup servo device.

Optical pickup 10; An A / D converter 20; Digital filter 30; Adder 40; Cutting means 50; Delay means 60; And a driving means (70), and a switch (110) provided between the delay unit (60) and the adder (40). And a level detection unit 100 for controlling whether the switch 110 is short-circuited based on the level size change amount between successive digital data output from the A / D converter 20.

Referring to the operation of the optical pickup servo device according to the present invention configured as described above are as follows.

In the optical pickup servo device 20 according to the present invention, an analog focusing error signal generated from the optical pickup 10 is detected from the optical pickup 10 in the same manner as usual, due to the surface shake phenomenon caused by the rotation of the CD. After the A / D converter 20 converts the 16-bit digital data, the digital filter 30 inputs the filter 40 through the low pass compensation and the high pass compensation.

This value is cut by the cutting means 50 through the above process and summed with the lower 8-bit value of the immediately preceding digital data delayed by one delay by the delay means 60 and output to the cutting means 50. After the lower 8-bit value is cut again, only the upper 8-bit value is input to the optical pickup driver 70, and the optical pickup driver 70 determines the current position of the optical pickup 10 based on this signal. By outputting the control signal in the direction of reducing the focusing error and the tracking error of (10), it is possible to perform servo control using only the upper 8-bit value, but more accurate servo control reflecting the lower 8-bit value of the previous data.

As described above, the level detection unit 100 performs servo control in a direction of correcting a focusing error and a tracking error of the optical pickup 20 based on the output value added to the currently read data and the value reflected therein. ) Continuously detects a focusing error signal output from the A / D converter 20, and when it is detected that the level change amount of the continuous error signal output by a sudden disturbance such as an unexpected disturbance is greater than or equal to a predetermined value. The detection unit 100 disconnects the switch 110 so that the lower 8-bit value of the immediately preceding data output by the delay means 60 is not temporarily input to the adding means 40. Accordingly, since the lower data of the data value having the ideal size is not reflected in the data value immediately after the disturbance, the optical pickup 10 can be more precisely controlled later.

On the other hand, if the level change amount of the continuous focusing error signal outputted from the A / D converter 20 falls below a predetermined value again, the level detector 100 short-circuits the switch 110 again to disconnect previous data. This is reflected in the servo control.

The optical pickup servo device according to the present invention configured as described above is a very useful invention having the effect of enabling accurate servo control even when there is a transient abnormality of a signal due to disturbance or the like.

Claims (3)

Data separating means for cutting out a lower value of a predetermined unit or less from the input digital data; Delay means for delaying the cut out lower value by a predetermined time; Adding means for adding the delayed lower value and the value of the currently read digital data to output the data to the data separating means; And driving means for controlling a reading position of the optical pickup based on a digital data value whose lower value is cut by the data separating means. Level change amount detecting means for detecting a change amount of a level size of the read digital data; And And a switching means for disconnecting the lower value from being input to the adding means when detecting the level change amount of a predetermined magnitude or more by the level change amount detecting means. The method of claim 1, And said switching means is formed between said delay means and said adding means. The method of claim 1, And said switching means is formed between said data separating means and said delay means.