KR100192235B1 - Rotational servo apparatus for different type optical disk - Google Patents

Abstract

The present invention relates to an apparatus for sharing some circuits for recording and reproducing heterogeneous optical discs having different disc thicknesses and recording densities. In particular, in a rotary servo apparatus of heterogeneous optical discs having different recording densities and thicknesses, data read from the disc is counted. A synchronization signal detector for detecting a synchronization signal corresponding to a format of a heterogeneous optical disk, and counting an output of the synchronization signal generator to predict a position at which a next synchronization signal is generated to generate a prediction synchronization signal corresponding to a format of a heterogeneous optical disk. By using a CD and DVD in common, a prediction signal generator and a window signal generator for counting the output of the synchronization signal detector and generating a window signal having a predetermined pulse width at the position where the synchronization signal is to be generated can be used in both CD and DVD. To reduce the number of gates in IC development and reduce costs Can.

Description

Heterogeneous optical disk rotary servo device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for sharing some devices in a disc player for recording and playing heterogeneous optical discs having different disc thicknesses and recording densities, and more particularly, to a servo controlling rotation of heterogeneous optical discs having different disc thicknesses and recording densities. The present invention relates to a heterogeneous optical disk rotary servo device which shares a synchronization signal detection circuit.

Recently, optical discs have a large recording capacity than conventional compact discs (hereinafter referred to as CDs) due to continuous development efforts to increase recording capacity. Has been developed.

A DVD has a higher recording density than a CD and a shorter distance from the surface of the disc to the information recording surface. In fact, the DVD has a distance of 0.6 mm from the surface of the disc to the information recording surface, while the CD has 1.2 mm.

CD has a track pitch of 1.6 µm, a pit length of 0.834 µm, a light source of 780 nm, an objective lens of 0.45, while a DVD has a track pitch of 0.74 µm, a pit length of 0.4 µm, and a light source wavelength of The numerical aperture of the objective lens is 650 nm and 0.60.

That is, the recording capacity of a DVD is 6 to 8 times that of a CD, and video and audio data compression is used, and one movie of the same image quality as that of the current TV broadcast is recorded on a disc having a diameter of 120 nm.

At this time, the data may be recorded on both sides of the disc or the recording surface may be formed in two layers to increase the recording capacity.

In addition, considering that a large amount of software in a CD format is used, a DVD needs to be able to play a CD. In other words, higher regeneration compatibility must be ensured.

In this case, since the DVD format has been released since the commercialization of the CD format, the formats of the CD and DVD are slightly different in each part.

Therefore, in the related art, as shown in FIG. 1, the rotation servo is separately configured for each format to control disk rotation.

At this time, the rotation servo that controls the disk motor for rotating the disk includes a synchronization signal read from the disk to drive the disk at a constant linear velocity (CLV), address information of a trace position, and a clock signal as a reference for a control operation. It contains various information such as command from microcomputer, and physical data format inputted to each rotary servo is NRZI type, but synchronization signal pattern and frame length are different.

Accordingly, the CD rotation servo 11 and the DVD rotation servo 12 are configured independently, and the CD rotation servo 11 and the DVD rotation servo 12 are respectively reproduced according to the type of disc to be reproduced, for example, CD or DVD. The output of the rotary servo 11 or the output of the DVD rotary servo 12 was selected to connect a multiplexer 13 for controlling the rotation of the disk motor to configure a CD / DVD combined servo.

At this time, when the CD or DVD is played back, the disc motor starts to rotate at a certain speed, and the optical pickup reads out the information recorded on the disc.

EFM (Eight to Fourteen Modulation) modulation for converting 8-bit data into 14-bit is performed on the read information, and the EFM-modulated data is non-return-to zero (inverted; NRZI) modulated simultaneously. The CD rotating servo 11 and the DVD rotating servo 12 are input.

The NRZI modulation is a modulation rule for inverting data in a signal of '1'. In other words, if '1' is met, the current state is reversed.

Therefore, the CD rotary servo 11 outputs a disc motor control signal conforming to the CD format, and the DVD rotary servo 12 outputs a disc motor control signal conforming to the DVD format.

At this time, if the disc type to be reproduced is CD, the output of the CD rotation servo 11 is output through the multiplexer 13, and if the DVD is output, the output of the DVD rotation servo 12 is output through the multiplexer 13.

As described above, in order to secure the upper compatibility of the DVD player, a CD rotating servo and a DVD rotating servo are respectively constructed and selectively used.

Therefore, there is a problem that the hardware amount of the rotary servo for controlling the rotation of the CD or DVD is increased, the configuration is complicated, and the cost is increased.

The present invention has been made to solve the above problems, and an object of the present invention is to develop an integrated circuit (IC) by reducing the amount of hardware of the rotary servo by using a common part of the synchronization signal generation used for phase comparison in the rotary servo. The purpose of the present invention is to provide a heterogeneous optical disk rotating servo device which reduces the number of gates and reduces costs.

In order to achieve the above object, a characteristic of a dual optical disc rotating servo device according to the present invention includes a synchronization signal detection unit for counting data read from a disc and detecting a synchronization signal corresponding to a format of a heterogeneous optical disc; A prediction synchronization signal generator for counting the output of the synchronization signal generator to predict the position at which the next synchronization signal is generated, and generating a prediction synchronization signal corresponding to the format of the heterogeneous optical disc; It is configured to include a window signal generator for generating a window signal having a predetermined pulse width at the position to be generated.

1 is a block diagram of a conventional rotary servo device for heterogeneous optical discs.

2 is a block diagram illustrating a configuration of a rotary servo device for heterogeneous optical disks according to the present invention.

3 (a) to 3 (e) are timing diagrams illustrating the operation of each part of FIG.

* Explanation of symbols for main parts of the drawings

20: synchronization signal detector 21, 31: counter

22: CD sync signal detector 23: DVD sync signal detector

24, 34, 43: multiplexer 30: prediction synchronization signal generator

32: CD predictive synchronization signal generator 33: DVD predictive synchronization signal generator

40: window signal generator 41: CD window signal generator

42: DVD window signal generator

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram showing the configuration of a rotary servo device for a heterogeneous optical disk according to the present invention, and in particular, a detailed block diagram of a synchronization generating circuit.

Referring to FIG. 2, a synchronization signal detection unit 20 for detecting a synchronization signal used for phase comparison from an NRZI modulated signal and the next synchronization in case the synchronization signal is not detected due to an error in the synchronization signal detection unit 20 are used. The prediction synchronization signal generator 30 generates a prediction synchronization signal by predicting a location from which the signal comes out, and generates a window signal at a location where the synchronization signal will be generated in order to reduce a synchronization signal detection error in the synchronization signal detector 20. It is configured to include a window signal generator 40.

The synchronization signal detection unit 20 includes a counter 21 for counting NRZI modulated signals, and a CD synchronization signal detection unit 22 and counter 21 for detecting a synchronization signal conforming to the CD format using the output of the counter 21. Selects and outputs the sync signal detected by the CD sync signal detector 22 or the DVD sync signal detector 23 according to the type of disc, according to the disc type It consists of a multiplexer 24.

The prediction synchronization signal generator 30 uses a counter 31 for counting the output signal of the synchronization signal detector 20 and a CD prediction synchronization for generating a prediction synchronization signal for a CD format using the output of the counter 31. The DVD predictive synchronous signal generator 33 for generating a predictive synchronous signal for the DVD format by using the signal generator 32, the output of the counter 31, and the CD predictive synchronous signal generator 32 according to the disc type. Or a multiplexer 34 for selectively outputting the predictive synchronization signal generated by the DVD predictive synchronization signal generator 33.

The window signal generator 40 uses the output of the counter 31 to match the DVD format by using the output of the CD window signal generator 41 and the counter 31 that generate a window signal conforming to the CD format. The DVD window signal generator 42 for generating a window signal, and the multiplexer 43 for selectively outputting the window signal generated by the CD window signal generator 41 or the DVD window signal generator 42 according to the disc type. It consists of.

In the present invention configured as described above, the counter 21 of the sync signal detector 20 counts the NRZI modulated signals and outputs them to the CD sync signal detector 22 and the DVD sync signal detector 23.

At this time, if the length of the pit counted as shown in Fig. 3 (a) is 11T and the pit and pit interval is 11T, the CD sync signal generator 22 determines that it is a CD sync signal and the third As shown in (b), a pulse is generated and output to the multiplexer 24.

Here, T is the length of one clock pulse and 11T is the length of 11 clock pulses.

In addition, if the length of the counted pit is 14T, the DVD synchronization generating unit 23 determines that the DVD is a synchronization signal, and generates a pulse at the position to output the pulse to the multiplexer 24.

At this time, the pulse generated by the CD synchronization signal detector 22 or the pulse generated by the DVD synchronization signal detector 23 becomes a detection synchronization signal.

The multiplexer 24 selects the output of the CD sync signal detector 22 when the type of the disc to be played is CD, and selects the output of the DVD sync signal detector 23 when the DVD is played and outputs the final sync signal. The counter 31 outputs to the counter 31 of the synchronization signal generator 30.

The counter 31 of the prediction synchronization signal generator 30 is in a disabled state and starts counting when a detection synchronization signal is input.

When the output of the counter 31 becomes a section between the CD detection synchronization signal and the next CD detection synchronization signal, the CD prediction synchronization signal generator 32 generates the CD prediction synchronization signal as shown in FIG. When the output of the counter 31 becomes a section between the DVD detection synchronization signal and the next DVD detection synchronization signal, the prediction synchronization signal generator 33 generates a DVD prediction synchronization signal and outputs it to the multiplexer 34.

The multiplexer 34 selects the output of the CD predictive synchronization signal generator 32 when the type of the disc to be reproduced is CD, and selects the output of the DVD predictive synchronization signal generator 33 when the DVD is a final predicted synchronization signal. Output

Here, the reason for generating the prediction synchronization signal is, for example, in order to prepare for the CD synchronization signal at the g position of FIG. 3 (a), when there is no synchronization signal to be compared with the reference synchronization when it is not detected by an error. In this case, the predictive synchronization signal is used for phase comparison.

On the other hand, when the output of the counter 31 becomes a section between the CD detection synchronization signal and the next CD detection synchronization signal, the CD window signal generation unit 41 uses the CD window signal as a CD window signal as shown in FIG. c) and the DVD window signal generator 33 generates a DVD window before and after the detection synchronization signal when the output of the counter 31 becomes a section between the DVD detection synchronization signal and the next DVD detection synchronization signal. It is generated as a signal and output to the multiplexer 34.

The multiplexer 43 selects an output of the CD window signal generator 41 when the type of the disc to be played is CD, and selects an output of the DVD window signal generator 42 to output the final window signal.

In this case, the window signal is regarded as having matched the synchronization pattern with respect to the error of a certain bit among the detection synchronization patterns, and the synchronization signal detected in the window generation section is generated to recognize the detection synchronization signal.

In order to reduce the synchronization detection error by acknowledging a synchronization signal that is somewhat out of a generated position as a detection synchronization signal, the window signal pulse width may vary depending on the designer.

For example, a synchronization signal outside the window section as in the f position of FIG. 3 (b) is not recognized as a detection synchronization signal, and a synchronization signal in the window section as in the h position of FIG. It is recognized as a detection synchronous signal.

If there is no synchronization signal coming into the window as in the i position of FIG. 3 (b), the prediction synchronization signal of FIG.

When the synchronization signal is detected as described above, the phase of the synchronization signal and the reference synchronization signal of FIG. 3E are compared and the rotation of the disk motor is controlled using the phase difference.

That is, the rotation speed of the disk motor is increased or decreased according to the phase difference until the phase difference between the reference synchronization and the detection synchronization is identical.

Since the CD and DVD share the large number of gates 21 and 31, and only the frame length and the length of the registered signal pattern are different, only the values of the remaining blocks except for the counters 21 and 31 are set for the CD or DVD. By doing so, it is possible to add a CD rotating servo to a DVD rotating servo with only minimal circuit addition.

The present invention can be designed such that the rest of the circuits other than the synchronous signal detection circuit can share a part of the circuit with the CD and the DVD.

As described above, according to the heterogeneous optical disk rotating servo device according to the present invention, CD and DVD share a circuit for generating a synchronization signal, a predicted synchronization signal, and a window signal considering phase error in the rotation servo. By reducing the amount of hardware in the rotary servo, the number of gates in IC development can be reduced, and the cost can be reduced.

Claims (4)

A rotation servo apparatus for heterogeneous optical discs having different recording densities and thicknesses, comprising: a synchronization signal detection unit for counting data read from the disc and detecting a synchronization signal corresponding to the format of the heterogeneous optical disc; A prediction synchronous signal generator for counting and predicting a position at which the next synchronous signal is generated to generate a predicted synchronous signal corresponding to a format of a heterogeneous optical disk, and counting the output of the synchronous signal detector to generate a predetermined pulse at a position where the synchronous signal is to be generated. A rotary servo apparatus for dual optical discs, characterized in that a window signal generator for generating a window signal having a width is commonly used for reproduction of heterogeneous optical discs having different recording densities and thicknesses. 2. The apparatus of claim 1, wherein the sync signal detector comprises: a counter for counting pulse signals of data read from a disc, a CD sync signal detector for detecting a sync signal conforming to a CD format using the output of the counter, Heterogeneous, comprising: a DVD sync signal detector for detecting a sync signal in accordance with a DVD format by using an output; and a multiplexer for selectively outputting a sync signal detected by the CD sync signal detector or a DVD sync signal detector according to a disc type Rotating servo device for optical disc. The apparatus of claim 1, wherein the prediction synchronization signal generator comprises: a counter for counting an output signal of the synchronization signal detector; a CD prediction synchronization signal generator for generating a prediction synchronization signal suitable for a CD format by using the output of the counter; A DVD predictive sync signal generator for generating a predictive sync signal suitable for a DVD format by using the output of the counter, and a predictive sync signal generated by the CD predictive sync signal generator or a DVD predictive sync signal generator according to a disc type. Rotating servo device for use with heterogeneous optical disks, characterized in that it consists of a multiplexer for selective output. The method of claim 1, wherein the window signal generation unit comprises: a counter for counting an output signal of the synchronization signal detection unit, a CD window signal generation unit for generating a window signal conforming to a CD format using the output of the counter, A DVD window signal generator for generating a window signal conforming to the DVD format by using an output and a multiplexer for selectively outputting the window signal generated by the CD window signal generator or the DVD window signal generator according to the type of disc; Heterogeneous optical disk combined rotary servo device.