KR0160712B1 - Reproducing apparatus for optical disc - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for reproducing an optical disc, wherein a decoding clock derived from a reference clock whose reproduction frequency differs depending on the radius of the disc is provided in the data buffer portion between the phase lock loop (PLL) circuit portion and the decoder. .

The apparatus of the present invention peaks the optical disk signal that has passed through the current / voltage conversion and pre-amp circuit 20 and the current / voltage conversion and pre-amp circuit 20 which receives a reproduction signal of the optical disk and outputs it as an analog voltage signal. The signal detection unit 22 for pulsed through the detection and zero cloth method, the phase locked loop (PLL) circuit unit 24 for generating a PLL clock to read the pulse signal output from the signal detection unit 22, and the phase A data buffer unit 26 for receiving a signal output from the synchronous loop (PLL) circuit unit 24 and outputting the signal to the decoder 28, and a reference clock for outputting data from the data buffer 26 to the decoder 28. It consists of a system control unit 32 for generating a.

Therefore, as described above, the optical disc reproducing apparatus uses a decoding clock derived from a reference clock having a different reproducing frequency depending on the radius of the disc as an output clock of the data buffer unit, thereby preventing data loss caused by data jams. I provide the effect.

Description

Device for playing optical discs.

1 is a block diagram of an input / output clock of a data buffer unit in the prior art.

2 is a block diagram of an input / output clock of a data buffer unit according to the present invention.

3 is a block diagram for implementing the present invention.

The present invention relates to an apparatus for reproducing an optical disc. More particularly, the present invention relates to an apparatus for reproducing an optical disc, wherein the data buffer between the phase lock loop (PLL) circuit unit and the decoder unit provides a decoded clock signal derived from a reference clock whose reproduction frequency varies depending on the disc radius. will be.

1 is a block diagram of an input and output clock of a data buffer in the prior art.

Referring to FIG. 1, the problems of the prior art will be described.

The apparatus of FIG. 1 includes a phase locked loop (PLL) circuit section 10 that detects a phase difference between an input signal and an oscillation output signal and detects a phase thereof, and inputs PLL data from the phase locked loop (PLL) circuit section 10. FIG. And a data buffer unit 12 which receives the output to the decoder 14.

The operation of this apparatus outputs the PLL data digitally processed by the phase locked loop (PLL) circuit section 10 receiving the reproduction signal to the data buffer section 12, and the PLL clock controls the output of the PLL data. The data buffer unit 12 that receives the PLL data inputs data to the decoder unit 14. In this case, the clock required for data transmission uses the same clock frequency as the clock used when outputting from the PLL circuit unit 10 to the data buffer unit 12. That is, the phase of the PLL clock is not constant according to the phase of the PLL data, and the period of the PLL clock is converted according to the radius of the optical disk.

The optical signal reproduced by an optical recording and reproducing apparatus (MODD) becomes data which is a digital signal including a reference clock pulse while passing through a PLL phase locked loop circuit. A buffer is required to input this data to the decoder, and the control signal for controlling the buffer is a clock generated by the phase locked loop (PLL) circuit part, but this PLL clock has a phase that is not constant according to the phase of the PLL data. The period is converted according to the radius of the disc. For example, if the optical head is moved to the outermost side of the disc at the lowest frequency, and the optical head moves to the outermost side of the disc at the lowest frequency, a certain time is required for the PLL clock to follow the PLL data. There is a high possibility of data loss due to a difference in clock frequency. As such, the data buffer must be output to the previous PLL clock before the PLL clock suitable for the newly reproduced signal is generated, and the previous data must be output before the data by the new PLL clock is inputted. This can happen if you lose this data.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and by using the decoding clock derived from the reference clock corresponding to the reproduction frequency according to the radius of the disc as the output clock of the data buffer, data jamming can be prevented from occurring. It is an object of the present invention to provide a reproducing apparatus.

A reproducing apparatus for an optical disc having a different reproducing frequency according to a radius of a disc according to the present invention, which achieves the above object, comprising: a phase locked loop (PLL) circuit unit generating a PLL clock for transmitting PLL data; A data buffer unit configured to receive PLL data from the phase locked loop (PLL) circuit unit; a system controller configured to generate a reference clock for each sector having a different reproduction frequency according to a radius of the disk; And a decoder which receives data of the data buffer unit by using a decoding clock derived from a reference clock generated from a system control as an output clock of the data buffer unit.

In the data buffer unit, a first in first out (FIFO) type buffer is used as the data buffer unit.

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

2 is a block diagram of an input / output clock of a data buffer unit according to the present invention.

The apparatus of FIG. 2 is the same as the apparatus of FIG.

Phase-locked loop (PLL) circuit section 20 for detecting phase by detecting a phase difference between an input signal and an oscillation output signal, and outputting the PLL data from the phase-locked loop (PLL) circuit section 20 to the decoder 24. It consists of a data buffer unit 22.

A distinct difference from the first diagram described in the related art is that the output clock signal is output to the data buffer unit 22 and the coding clock derived from the reference clock for each color that has a different frequency according to the radius of the disk is outputted from the data buffer unit 22. It is used as a clock.

A more detailed description will be given below with reference to FIG. 3.

3 is one embodiment to achieve the present invention.

The apparatus shown in FIG. 3 receives an optical disk signal which has passed the current / voltage conversion and pre-amp circuit 30 and the current / voltage conversion and pre-amp circuit 30 which receives a reproduction signal of the optical disk and outputs it as an analog voltage signal. A signal detector 32 for pulsed through a peak value detection and zero cloth method, a phase locked loop (PLL) circuit portion 34 for generating a PLL clock for reading a pulse signal output from the signal detector 32, A data buffer unit 336 for receiving a signal output from the phase locked loop (PLL) circuit unit 34 and outputting the signal to the decoder 38, and for outputting data from the data buffer unit 36 to the decoder unit 38. And a system controller 42 for generating a reference clock frequency.

The operation rate of the device will be described.

First, the optical regeneration signal read from the optical disc becomes a voltage signal through the current / voltage conversion and pre-amp circuit 30, and the signal detection unit 32 becomes a pulse signal through the peak value detection and the zero cloth method. . In order to read this pulse signal, the phase-locked loop (PLL) circuit section 34 generates a synchronous PLL clock to become a digitized signal. In general, the phase-locked loop (PLL) circuit portion 34 transmits a reference signal in a constant region of a certain period reproduced from an optical disc to a reference clock of the phase-locked loop (PLL) circuit portion, that is, the entire system in a predetermined radius of the disc. Use it as the reference clock. The reference signal has a period twice the phase synchronization signal.

In addition, in the format of the disc, the track is divided into several sectors according to the size of a certain data, and the clock for reproducing in this sector operates the phase locked loop (PLL) circuit part on the basis of the reference signal. Therefore, until the reference signal in the next sector is input by a certain length, the phase locked loop (PLL) circuit portion is operated by a click corresponding to the reference period in the previous sector to produce a digital signal. In other words, when the SEEK movement (long-distance movement within the radius of the disc) is accelerated, data input at high speed may be lost if all of them cannot be output within the time of moving from one point of the disc radius to another. Here, moving from one point of the disk radius to another is equivalent to moving the frequency of the signal from high to low frequencies. In addition, the reference clock stores the signal frequency according to the radius of the disk on the ROM in advance, and the system control unit operates so that the frequency of the position where the optical pickup of the disk is to be moved at the same time as the SEEK command is generated.

As described above, the optical disc reproducing apparatus has an effect of preventing data loss caused by data jam by using a decoding clock derived from a reference clock having a different reproducing frequency according to the radius of the disc as an output clock of the data buffer unit. To provide.

Claims (2)

A phase locked loop (PLL) circuit section for generating a PLL clock for transmitting PLL data in an optical disc reproducing apparatus having a different reproducing frequency according to a radius of the disc; A data buffer unit for receiving PLL data from the phase locked loop (PLL) circuit unit by the PLL clock; A system control unit for generating a reference clock for each sector having a different reproduction frequency according to a radius of the disc; And a decoder unit receiving data of the data buffer unit by using a decoding clock derived from the reference clock generated from the system control as an output clock of the data buffer unit. An apparatus for reproducing an optical disc according to claim 1, wherein a first in first out (FIFO) buffer is used as the data buffer unit.