CN1315122C - Tracking error signal generating device and generating method - Google Patents

Abstract

The invention relates to a tracking error signal generating device and method, which is applied to an optical reading device, wherein the optical reading device comprises an optical reading head, and the generating device comprises: a tracking error signal generator; a tracking error signal DC detection device and a comparator, and the generating method comprises the following steps: the tracking error signal generator responds to the change of the optical signal received by the optical reading head to generate a tracking error signal; the tracking error signal direct current detection device responds to the real-time change of the tracking error signal and continuously outputs a direct current voltage of the tracking error signal; the comparator responds to the magnitude relation between the direct current voltage and a reference voltage to send out a compensation signal; and a tracking error signal generator for correcting an offset voltage of the tracking error signal in response to a change in the compensation signal.

Description

Tracking error signal generating device and generating method

technical field

The invention relates to a tracking error signal generating device and a generating method, in particular to a tracking error signal generating device and a generating method applied to an optical reading device.

Background technique

Please refer to FIG. 1, which is a schematic diagram of the direction of movement of an optical pick-up head 10 arranged in an optical pick-up device such as an optical drive. It mainly moves in two directions. The first direction is the focusing direction perpendicular to the surface of the optical disc ( Focusing direction, referred to as F), and the second direction is the tracking direction (tracking direction, referred to as T) parallel to the surface of the disc. In order to perform feedback control on the movement of the optical reading head in the tracking direction, the functional block diagram shown in Figure 2 generates a tracking error signal (Tracking Error, TE for short) to provide a reference for the control system, optical reading The optical sensor 20 on the head receives the laser light reflected from the optical disc to produce six signals of A, B, C, D, E and F, and sending the E and F signals into an operational amplifier 21 will result in a signal as shown in Figure 3 ( a) Tracking error signal (TE) shown.

In an ideal situation, the tracking error signal (TE) is an AC voltage signal with zero DC component, and when the amplitude of the tracking error signal (TE) is zero, it represents the best state of tracking, so the tracking error signal (TE) The zero point is an important reference point for feedback control, but in fact, the tracking error signal (TE) generated by the optical sensor 20 and the operational amplifier 21 of the optical pickup head will have some DC components mixed into the tracking error signal (TE). error signal (TE), and the level of the tracking error signal (TE) shifts (as shown in Figure 3(b)), resulting in the actual zero point not coincident with the ideal zero point, and in order to improve this problem, An offset compensation operation for adjusting the DC level of the tracking error signal (TE) is introduced. The offset compensation action is mainly to modify the offset voltage (offsetvoltage) of the operational amplifier 21 to offset the DC component that should not exist originally, so as to match the actual zero point of the tracking error signal (TE) with the ideal The error of the zero point is reduced.

However, in the conventional technical means at present, most of them only calculate a fixed offset voltage value (offset voltage) during the calibration action performed during the start-up period of the optical drive, and then continuously provide it to the operational amplifier 21 for correction. However, with the change of the rotational speed of the optical drive and the position of the inner and outer tracks of the optical pick-up head 10, or the quality of the read optical disc is poor, the DC component of the tracking error signal will be generated at different positions and different rotational speeds. Large changes, so that the tracking error zero cross signal (Tracking Error Zero Cross, TEZC) generated by the tracking error signal (TE) will also be wrong, so that the optical pickup head 10 uses the tracking error zero cross signal When judging the direction of track jumping, it is very likely that the wrong direction of jumping will occur due to the wrong waveform of the tracking error zero-crossing signal. If this situation occurs when the optical pickup head 10 wants to move from the outer ring When reaching the inner ring position, it is likely to cause the optical pickup head 10 to move outward improperly due to misjudgment of the track jumping direction, or even collide with other parts of the optical drive, resulting in damage. Furthermore, an inappropriate offset voltage will also cause the waveform of the tracking error signal to be asymmetrical up and down, which will affect the performance of the track jump. How to improve the above deficiency is the main purpose of the present invention.

Contents of the invention

The invention relates to a tracking error signal generating device, which is applied to an optical reading device. The optical reading device includes an optical reading head, and the generating device includes: a tracking error signal generator, the signal is connected to the optical reading device The reading head, the tracking error signal generator generates a tracking error signal in response to the change of the optical signal received by the optical reading head; a tracking error signal DC detection device is electrically connected to the tracking error signal generator, the The tracking error signal DC detecting device responds to the input of the tracking error signal generated by the tracking error signal generator and outputs a DC voltage of the tracking error signal; and a comparator is electrically connected to the tracking error signal DC detecting device and a Reference voltage, the comparator sends a compensation signal to the tracking error signal generator in response to the magnitude relationship between the DC voltage output by the tracking error signal DC detection device and the reference voltage, and the tracking error signal generator can respond to the The offset voltage of the tracking error signal is corrected by compensating for the variation of the signal.

According to the above idea, in the tracking error signal generator of the present invention, the tracking error signal generator is implemented by an operational amplifier.

According to the above idea, the tracking error signal generating device of the present invention, wherein the tracking error signal DC detecting device includes: a resistor electrically connected to the output terminal of the tracking error signal generator; a capacitor electrically connected to the between the resistor and the reference voltage; and a signal output terminal disposed on the node between the resistor and the capacitor, the signal output terminal is used to output a low-pass voltage signal representing the DC voltage of the tracking error signal .

According to the idea above, in the tracking error signal generating device of the present invention, wherein the comparator is configured to correct the offset voltage of the tracking error signal so that the DC voltage close to this reference voltage.

According to the above idea, in the tracking error signal generating device of the present invention, the comparator performs the comparison between the DC voltage and the reference voltage before the optical pick-up head starts to jump from the outer ring to the inner ring of the disc. The comparison action changes the level of the compensation signal.

Another aspect of the present invention is a method for generating a tracking error signal, which is applied to an optical reading device, and the optical reading device includes an optical reading head, and the generating method includes the following steps: responding to the optical reading A tracking error signal is generated by the change of the optical signal received by the head; a DC voltage of the tracking error signal is continuously output in response to the real-time change of the tracking error signal; a compensation is issued in response to the magnitude relationship between the DC voltage and a reference voltage signal; and modifying the offset voltage of the tracking error signal in response to changes in the compensation signal.

According to the above idea, in the method for generating a tracking error signal of the present invention, the tracking error signal can be generated by an operational amplifier electrically connected to the optical pickup head.

According to the above idea, the tracking error signal generation method of the present invention, wherein the DC voltage of the tracking error signal is a low-pass voltage signal of the tracking error signal.

According to the idea above, in the tracking error signal generation method of the present invention, when the DC voltage is greater than the reference voltage, the compensation signal sent out will correct the offset voltage of the tracking error signal so that the DC voltage is close to the reference voltage .

According to the above idea, the tracking error signal generation method of the present invention is to compare the DC voltage with the reference voltage before the optical pick-up head starts to jump from the outer ring to the inner ring of the disk. The level of the compensation signal is varied.

Brief description of the drawings

The present invention can obtain deeper understanding with the help of following drawings and detailed description:

FIG. 1 is a schematic diagram of the moving direction of an optical reading head disposed in an optical reading device.

FIG. 2 is a schematic diagram of a conventional functional block for generating a tracking error signal.

Fig. 3(a)(b) is a schematic diagram of waveforms of various tracking error signals.

FIG. 4 is a schematic functional block diagram of a preferred embodiment of a tracking error signal generating device developed to improve conventional missing in the present invention.

FIG. 5 is a flow chart of the method for judging when to start the correction function in the present invention.

Description of reference symbols

Light sensor 20 Operational amplifier 21

Light sensor 40 Operational amplifier 41

Tracking error signal DC detection device 42 Output terminal 420

Resistor 421 Capacitor 422

Comparator 43 Optical read head 10

Detailed ways

Please refer to FIG. 4 , which shows a functional block diagram of a preferred embodiment of the tracking error signal generating device developed to improve the customary loss of the present invention, wherein the optical sensor 40 on the optical pickup head receives the laser light reflected from the optical disc Six signals A, B, C, D, E and F are generated, and the E and F signals are sent to a tracking error signal generator completed by an operational amplifier 41 to obtain a tracking error signal (TE). The main feature of the present invention is to add a tracking error signal DC detection device 42, which can respond to the input of the tracking error signal (TE) generated by the operational amplifier 41 and output the tracking error signal (TE) through its output terminal 420. A DC voltage of the tracking error signal.

As shown in the figure, the tracking error signal DC detection device 42 includes a resistor 421 and a capacitor 422, which mainly constitute a low-pass filter to detect the low-frequency DC signal of the tracking error signal (TE), Furthermore, a low-pass voltage signal representing the DC voltage of the tracking error signal (TE) is output through the output terminal 420 . By comparing the low-pass voltage signal with the reference voltage Vref by a comparator 43, a compensation signal can be sent to the DC voltage in response to the magnitude relationship between the DC voltage output by the tracking error signal DC detection device and the reference voltage Vref. An operational amplifier 41, and the operational amplifier 41 can modify the offset voltage of the tracking error signal in response to the change of the compensation signal.

For example, when the DC voltage is greater than the reference voltage Vref, the comparator 43 uses the compensation signal sent out to correct the offset voltage of the tracking error signal so that the DC voltage is close to the reference voltage. Therefore, the tracking error signal (TE) DC voltage can be adjusted downward. Similarly, when the DC voltage is lower than the reference voltage Vref, the compensation signal can adjust the DC voltage of the tracking error signal (TE) upward. In this way, the DC voltage of the tracking error signal (TE) will be adjusted at any time, even with the change of the rotation speed of the optical drive and the change of the position of the inner and outer tracks of the optical pickup head, or the quality of the read optical disc. Unfortunately, the DC component of the tracking error signal generated by the technology of the present invention does not change greatly at different positions and different rotational speeds, which can effectively improve the lack of conventional means.

In addition, when the optical pickup head wants to jump from the outer ring position to the inner ring position, the optical pickup head is improperly moved outward due to misjudgment of the track jump direction and collides with the optical drive, especially causing damage. Therefore, the present invention can still judge according to the position of the optical pick-up head (for example, represented by the number of tracks). The comparator 43 is turned on by an enable signal to compare the DC voltage with the reference voltage before the inner ring starts to perform the rail-jump action, thereby changing the level of the compensation signal. In this way, the frequent operation of the comparator 43 can be avoided to achieve the purpose of saving power, but it can also effectively improve the lack of collision of the optical pickup head. Please refer to FIG. 5 for a flow chart of the method for the above judgment mechanism.

To sum up, the present invention can effectively improve the habitual deficiency and achieve the main purpose of developing the present invention. Therefore, the present invention can be modified in various ways by those who are familiar with the art, and all of them are not separated from the attached patent application. Those who want to protect the range.

Claims (10)

1. a tracking error signal generation device is applied to an optical pickup device, include an optical read head in this optical pickup device, and this generation device comprises:

One tracking error signal generator, signal is connected in this optical read head, and this tracking error signal generator responds the variation of the light signal that this optical read head receives and a tracking error signal that computing produces;

One tracking error signal direct current pick-up unit, be electrically connected on this tracking error signal generator, this tracking error signal direct current pick-up unit responds the input of this tracking error signal that this tracking error signal generator produces and exports a direct current voltage of this tracking error signal; And

One comparer, be electrically connected on this a tracking error signal direct current pick-up unit and a reference voltage, this comparer responds the magnitude relationship of this DC voltage that this tracking error signal direct current pick-up unit exported and this reference voltage and sends a compensating signal to this tracking error signal generator, and this tracking error signal generator can respond this varying compensation and revise an offset voltage of this tracking error signal.

2. tracking error signal generation device as claimed in claim 1, wherein, this tracking error signal generator is finished by an operational amplifier.

3. tracking error signal generation device as claimed in claim 1, wherein, this tracking error signal direct current pick-up unit comprises:

One resistor is electrically connected on the output terminal of this tracking error signal generator;

One capacitor is electrically connected between this resistor and this reference voltage; And

One signal output part is arranged on the node between this resistor and this capacitor, and this signal output part is represented a low pass voltage signal of this DC voltage of this tracking error signal in order to output.

4. tracking error signal generation device as claimed in claim 1, wherein, this comparer is that this offset voltage that makes this compensating signal that is sent can revise tracking error signal makes this DC voltage near this reference voltage when this DC voltage during greater than this reference voltage.

5. tracking error signal generation device as claimed in claim 1, wherein, this comparer be this optical read head by the disc outer ring before inner ring begins to jump onto the tracks action, carry out the comparison of this DC voltage and this reference voltage and change this this compensating signal.

6. a tracking error signal production method is applied to an optical pickup device, include an optical read head in this optical pickup device, and this production method comprises the following step:

Respond the variation of the light signal that this optical read head receives and produce a tracking error signal;

Respond the real-time change of this tracking error signal and continue a direct current voltage of this tracking error signal of output;

Respond the magnitude relationship of this DC voltage and a reference voltage and send a compensating signal; And

Respond this varying compensation and adjust this tracking error signal offset voltage of correction of this tracking error signal.

7. tracking error signal production method as claimed in claim 6, wherein, this tracking error signal can be produced by an operational amplifier that is electrically connected on this optical read head.

8. tracking error signal production method as claimed in claim 6, wherein, this DC voltage of this tracking error signal is a low pass voltage signal of this tracking error signal.

9. tracking error signal production method as claimed in claim 6, wherein, when this DC voltage during greater than this reference voltage, this offset voltage that makes this compensating signal that is sent can revise tracking error signal makes this DC voltage near this reference voltage.

10. tracking error signal production method as claimed in claim 6, wherein, be this optical read head by the disc outer ring before inner ring begins to jump onto the tracks action, carry out the comparison of this DC voltage and this reference voltage and change this compensating signal.

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