KR100260709B1 - Synchronous Signal Generator in Optical Disc Playback System - Google Patents

Abstract

The synchronization signal generator of the optical disc reproducing system according to the present invention is for generating a signal synchronized with the frequency and phase of a signal reproduced from the optical disc. The apparatus of the present invention includes RF means for receiving data read out from the above-described optical disc to perform a predetermined process, and generating and outputting a high frequency reproduction (RF) signal and a wobble signal, respectively, as a result of the processing. The apparatus of the present invention also includes wobble synchronous signal generating means for generating a signal synchronized with the phase of the wobble signal received from the aforementioned RF means. Subsequently, the apparatus of the present invention receives a high frequency reproduction (RF) signal received from the above-described RF means and a wobble sync signal output from the wobble sync signal generating means, respectively, to detect a predetermined phase deviation and a frequency deviation, and detect the detected phase. RF synchronization signal generating means for generating a predetermined synchronization signal for stable data reproduction using the deviation and the frequency deviation. The apparatus of the present invention having such a configuration provides the effect of generating a faster and more stable synchronization signal than the conventional one by generating a predetermined synchronization signal for data reproduction using the wobble signal and the RF signal.

Description

Synchronous Signal Generator in Optical Disc Playback System

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for generating a signal synchronized with a frequency and phase of a signal reproduced from an optical disc. More particularly, the present invention relates to a synchronization signal generator of an optical disc reproducing system in which a wobble signal is recorded.

In general, an optical disc reproducing system requires a synchronization signal in order to accurately reproduce data recorded on an optical disc. A device for generating such a synchronization signal is a phase locked loop (PLL) circuit, which generates a signal synchronized with the frequency and phase of an input signal. A synchronizing signal generating apparatus in a conventional optical disc reproducing system having such a function will be described with reference to FIG.

The apparatus of FIG. 1 comprises an optical disc 101 and pickup means 102. The optical disc 101 is an optical recording medium on which data for reproduction is recorded, and the pickup means 102 scans an optical beam onto the optical disc 101 to detect light reflected from the optical disc 101 and records it on the optical disc 101. Read the generated data. The apparatus of FIG. 1 then comprises RF means 103. The RF unit 103 generates and outputs a high frequency reproduction (RF) signal by amplifying, reproducing the waveform, and performing waveform shaping.

On the other hand, the apparatus of FIG. 1 includes a phase detector 104 and a frequency detector 105. The phase detector 104 receives an RF signal output from the RF means 103 and a signal fed back from a voltage controlled oscillator (VOC), respectively, and receives the received signals. The phases are compared and the deviation is detected and output. In addition, the frequency detector 105 receives the RF signal output from the RF means 103 and the signal fed back from the voltage controlled oscillator 109 like the phase detector 104, and compares the frequencies of the two received signals. Detect and output the deviation. The adder 106 receives the phase deviation signal received from the phase detector 104 and the frequency deviation signal received from the frequency detector 105, respectively, and adds the two. The adder 106 outputs the added signal.

Compensation means 107 connected to the output terminal of the adder 106, when a defect of the RF signal output from the RF means 103 is detected, and compensates for it and outputs it. The compensating means 107 includes a defect detection section 107a, an average value calculation and holding section 107b, and a selector 107c. The defect detection unit 107a receives a signal output from the RF means 103 to detect a defect section, and generates and outputs a detection signal corresponding thereto. On the other hand, the average value calculation and hold unit 107b receives the signal output from the adder 106 described above, calculates a predetermined average value, and holds the calculated average value. The selector 107c selects and outputs a signal received from the above-described adder 106 when a signal indicating that the defect section is not defective is applied from the defect detection unit 107a, and detects that the detection signal indicating the defect section is received from the defect detection unit 107a. When applied, the signal received from the above-described average value calculation and hold unit 107b is selected and output.

Then, the loop filter 108 is connected to the output terminal of the selector 107c. The loop filter 108 removes and outputs noise and high frequency components included in a signal received from the selector 107c. A voltage controlled oscillator 109 is connected to the output terminal of the loop filter 108. The voltage controlled oscillator 109 receives the output of the loop filter 108 and generates and outputs a signal having a frequency and a phase corresponding thereto. Here, the output of the voltage controlled oscillator 109 is used as a synchronization signal for data reproduction. In addition, the output of the voltage controlled oscillator 109 is simultaneously fed back to the inputs of the above-described phase detector 104 and the frequency detector 105 to be used to detect the phase deviation and the frequency deviation with the RF signal.

However, the above-described synchronous signal generating apparatus of the optical disc reproducing system distinguishes the header area from the user area for recording data, such as DVD-RAM (Digital Multi-Function Disk RAM) or MOD (Magnet-Magnetic Disc) which can be recorded by the user. For the purpose of reproducing an optical disc in which no gap is recorded, that is, a blank section is set periodically, a stable synchronization signal for reproducing data cannot be generated.

More specifically with reference to FIG. 2, in the optical disc having the structure of FIG. 2A, a blank area is set as a header area, a user area in which actual data is recorded, and a gap for distinguishing the header area from the user area. have. Fig. 2B shows the timing of the header detection signal, Fig. 2C shows the timing of the blank detection signal, and Fig. 2D shows defects in the actual data recorded in the user area. Indicates the timing of a defect detection signal detected when a) is generated.

In the case of reproducing an optical disc having the structure as shown in FIG. 2 (a), since the conventional sync signal generator has no RF signal to detect phase in the blank section as shown in FIG. There is a problem in that fast and stable data reproduction cannot be performed by failing to detect frequency.

On the other hand, the above-described user recordable DVD-RAM (Digital Multi-function Disk-RAM) or MOD (Magnetic-Magnetic Disc) has a variety of functions such as optical disk rotation control or motor control, except for the header area and the defect section. The wobble signal for use for the purpose is recorded in advance in a guide groove or the like. Such a wobble signal is a sine wave signal having a predetermined frequency, and is generally determined at a specific frequency according to the type of disk.

SUMMARY OF THE INVENTION An object of the present invention for solving the above problems is to provide a synchronization signal generating apparatus which enables fast and stable data reproduction by generating a synchronization signal using the above-described wobble signal and RF signal during reproduction of an optical disc having a blank section. Is in.

1 is a synchronization signal generating apparatus of a conventional optical disc reproducing system,

FIG. 2 is a timing diagram showing the detection timing of a state of an optical disc with a wobble signal and a corresponding header, blank and defect section; FIG.

3 is a synchronization signal generator of an optical disc reproducing system according to the present invention;

<Description of the symbols for the main parts of the drawings>

101: optical disk 102: pickup means

103,310: RF means 104,322,331: phase detector

105,332: frequency detector 106: adder

107,323,333: Compensation means 107a: Defect detection unit

107b, 323b, 333b: Average value calculation and hold part 107c, 323c, 333c: Selector

108: loop filter 109,324: voltage controlled oscillator

320: wobble synchronous signal generating means 321: binarizer

323a: wobble detector 330: RF synchronization signal generating means

333a: blank detection unit

An apparatus of the present invention for achieving the above object is a device for generating a signal synchronized with the frequency and phase of a signal reproduced from an optical disc, the data received from the optical disc to perform a predetermined process, the processing result is a high frequency RF means for generating and outputting a reproduction (RF) signal and a wobble signal, respectively. The apparatus of the present invention also includes wobble synchronous signal generating means for generating a signal synchronized with the phase of the wobble signal received from the RF means. Then, the apparatus of the present invention is characterized in that the phase deviation of the high frequency reproduction (RF) signal received from the RF means and the signal fed back from the second voltage controlled oscillator, and the signal received from the above-described wobble synchronization signal generating means; And an RF synchronous signal generating means for obtaining a frequency deviation of a signal fed back from the second voltage controlled oscillator and generating a predetermined synchronization signal for stable data reproduction using the obtained phase deviation and frequency deviation.

Hereinafter, with reference to the accompanying Figure 3 will be described in detail a preferred embodiment of the present invention.

The apparatus of FIG. 3 comprises a pickup means 102 and an RF means 310. The pickup means 102 reads out data from the optical disc 101 and outputs it. The RF means 310 receives the output of the pickup means 102 and performs predetermined processing such as amplification, waveform equalization, waveform shaping, etc., and generates and outputs a radio frequency reproduction (RF) signal and a wobble signal as a result of the processing. . In this case, the wobble signal may be generated by configuring a separate circuit.

The apparatus of FIG. 3 then comprises wobble synchronous signal generating means 320 for generating a signal synchronized with the phase of the wobble signal received from RF means 310. More specifically, the wobble sync signal generating means 320 includes a binarizer 321. The binarizer 321 receives the wobble signal from the RF means 310, converts it into a digital signal, and outputs the digital signal. The first phase detector 322 is connected to the output terminal of the binarizer 321. The first phase detector 322 receives the outputs of the binarizer 321 and the divider 325 to be described later, compares the phases of the two received signals, and detects and outputs a deviation.

Subsequently, a first voltage controlled oscillator 324 is connected to an output terminal of the first phase detector 322. The first voltage controlled oscillator 324 (VCO) generates a signal corresponding to the phase deviation received from the first phase detector 322. The output signal of the first voltage controlled oscillator 324 is input to the frequency detector 332 and the divider 325 shown in FIG. The divider 325 receives the output of the first voltage controlled oscillator 324 and divides the output at an appropriate ratio. At this time, the frequency divider 325 sets the frequency division ratio to an appropriate value for smoothing the output of the first voltage controlled oscillator 324. The output signal of the frequency divider 325 is fed back to the first phase detector 322 and used to detect a phase deviation from the binarized wobble signal, whereby the wobble synchronous signal generating means 320 receives the received signal. When the phase of the wobble signal is changed, it is possible to generate a signal synchronized with it.

Further, the wobble synchronous signal generating means 320 of the apparatus of FIG. 3 further includes a first compensating means 323 between the first phase detector 322 and the first voltage controlled oscillator 324 to prevent the wobble signal from being received. Even in this case, it can be configured to generate a stable wobble sync signal. In this case, the first compensation means 323 includes a wobble detection unit 323a for receiving a wobble signal from the RF means 310 to generate and output a wobble detection signal corresponding to the presence or absence of a wobble signal. At this time, the wobble detection signal has different levels in the section with the wobble signal and the section without the wobble signal. In addition, in the user recordable optical disc 101, a section without a wobble signal generally corresponds to a header area and a defective section as described above. Accordingly, the wobble detector 323a may be configured by a header detector that detects the header area and a defect detector that detects a defect section. On the other hand, the first compensating means 323 includes a first average value calculating and holding part 323b and a first selector 323c for receiving the output of the first phase detector 322, respectively. The first average value calculation and hold unit 323b receives the output of the first phase detector 322 and calculates a predetermined average value, and when there is no output of the first phase detector 322, it is held and outputted. Can be configured. Meanwhile, the first selector 323c, which receives the output of the first phase detector 322 and the first average value, respectively selects one of the two signals received according to the wobble detection signal applied from the wobble detector 323a. Output At this time, the first selector 323c selects and outputs a signal received from the first phase detector 322 in a section in which there is a wobble signal, and receives the signal from the first average value calculation and hold unit 323b in a section in which there is no wobble signal. Select and output the signal. The first compensation means 323 having such a configuration and function has an advantage of generating a stable wobble sync signal by compensating with the average value signal when the wobble signal is not received.

On the other hand, the apparatus of Figure 3 includes an RF synchronization signal generating means 330. The RF synchronous signal generating means 330 receives the RF signal output from the RF means 310 and the signal output from the wobble synchronous signal generating means 320 to obtain a predetermined phase deviation and a frequency deviation, respectively. A predetermined synchronization signal for data reproduction is generated using the frequency deviation. More specifically, the RF synchronization signal generating means 330 includes a second phase detector 331 and a frequency detector 332. The second phase detector 331 receives an RF signal output from the RF means 310 and a signal fed back from the second voltage controlled oscillator 109, compares phases, and detects and outputs a phase deviation. In addition, the frequency detector 332 receives the output of the wobble sync signal generating means 320 and the signal fed back from the second voltage controlled oscillator 109, compares frequencies, and detects and outputs a frequency deviation. The signals output from the second phase detector 331 and the frequency detector 332 are input to the adder 106, respectively.

Subsequently, the RF synchronization signal generating means 330 of the apparatus of FIG. 3 includes an adder 106, a third compensating means 107, a loop filter 108, and a second voltage controlled oscillator 109 having the same configuration as the apparatus of FIG. It is provided. However, each configuration described above receives a signal different from that of the apparatus of FIG. 1 and performs a predetermined process. Here, the third compensation means 107 and the second voltage controlled oscillator 109 of the apparatus of FIG. 3 correspond to the compensation means 107 and the voltage controlled oscillator 109 of the apparatus of FIG.

More specifically, the adder 106 receives the outputs of the second phase detector 331 and the frequency detector 332, respectively, and adds the received signals to each other to output them. The third compensation means 107 connected to the output terminal of the adder 106 compensates and outputs the averaged signal in the section where the defect is detected. The loop filter 108 connected to the output terminal of the third compensation means 107 removes and outputs noise and high frequency components included in the received signal. The second voltage controlled oscillator 109 connected to the output of the loop filter 108 generates a signal having a frequency and a phase corresponding to the signal received from the loop filter 108. At this time, the output signal of the second voltage controlled oscillator 109 is used as a synchronization signal for reproducing the data of the optical disk 101, and is fed back to the second phase detector 331 and the frequency detector 332 at the same time so that the phase deviation and the frequency deviation are It is used to detect.

On the other hand, the RF synchronization signal generating means 330 of the apparatus of FIG. 3 further includes a second compensation means 333 between the second phase detector 331 and the adder 106, thereby blanking the optical disc 101. In the section, the output of the second phase detector 331 can be compensated with an averaged signal and output to the adder 106 so that stable phase detection can be performed even on the optical disc 101 having a blank section.

More specifically, as shown in FIG. 3, the second compensation means 333 includes a blank detection unit 333a, a second average value calculation and hold unit 333b, and a second selector 333c. The blank detection unit 333a determines the presence or absence of an RF signal output from the RF means 310, and generates a detection signal having a different level than that in the section where the RF signal is present whenever a blank section without the RF signal is detected. To print. On the other hand, the second average value calculation and hold unit 333b receives the output of the second phase detector 331 and calculates an average value, and when the blank section is detected, the average value signal is held and output. In addition, two second selectors 333c which receive the outputs of the second phase detector 331 and the second average value calculation and hold unit 333b are respectively received according to the blank detection signal applied from the blank detection unit 333a. Select one of the signals and output it. At this time, the second selector 333c selects a signal received from the second phase detector 331 in the section where the blank is not detected and outputs the signal to the adder 106, and in the section where the blank is detected, the second average value calculation and hold unit. A signal received from 333b is selected and output to the adder 106. The apparatus of FIG. 3 further includes a second compensating means 333 having such a configuration, which allows the fast and stable phase detection even in the blank section.

Referring to the operation of the apparatus of FIG. 3 having such configurations, the apparatus of FIG. 3 generates a wobble sync signal synchronized with the phase of the wobble signal reproduced from the optical disc 101 and uses it as an input of the frequency detector 332. Subsequently, the frequency detector 332 receives a signal fed back from the second voltage controlled oscillator 109 to detect and output a frequency deviation from the wobble sync signal. In addition, the apparatus of FIG. 3 detects and outputs a phase deviation between the RF signal reproduced from the optical disc 101 and the signal fed back from the second voltage controlled oscillator 109. The detected phase deviation and frequency deviation are input to the adder 106 and added to each other. The loop filter 108 receives the output of the adder 106 and removes noise and high frequency components to output the same. The second voltage controlled oscillator 109 generates a synchronization signal having a frequency and a phase corresponding to the output of the loop filter 108. The output of the second voltage controlled oscillator 109 is used as a synchronization signal for reproducing data, and is fed back to the second phase detector 331 and the frequency detector 332 described above. Accordingly, the apparatus of FIG. 3 has an advantage of generating a more stable synchronization signal by generating a predetermined synchronization signal for data reproduction using the wobble signal and the RF signal.

On the other hand, the apparatus of FIG. 3 further includes a first compensation means 323 and a second compensation means 333 to compensate by a predetermined average value signal when a wobble signal is not detected or a blank section is detected. An advantage is to generate a synchronization signal for fast and stable data reproduction.

The apparatus of the present invention provides the effect of enabling a faster and more stable data reproduction than the conventional one by generating a predetermined synchronization signal for data reproduction using the wobble signal and the RF signal. In particular, the apparatus of the present invention further includes a first compensating means and a second compensating means to provide an effect of stably generating a predetermined synchronizing signal even when there is no wobble signal and when a blank section is detected.

Claims (11)

An apparatus for generating a signal synchronized with a frequency and a phase of a signal reproduced from an optical disc, RF means for receiving a data signal read out from the optical disc and performing a predetermined process, and generating and outputting a high frequency reproduction (RF) signal and a wobble signal, respectively, as a result of the processing; Wobble synchronous signal generating means for generating a signal synchronized with the phase of the wobble signal received from the RF means; And A phase deviation of a high frequency regeneration (RF) signal received from the RF means and a signal fed back from the second voltage controlled oscillator, and a signal received from the wobble synchronous signal generating means and the second voltage controlled oscillator And an RF synchronization signal generating means for obtaining a frequency deviation of a signal to be fed back and generating a predetermined synchronization signal for stable data reproduction using the obtained phase deviation and frequency deviation. The method of claim 1, wherein the wobble sync signal generating means A binarizer for binarizing the wobble signal received from the RF means; A first phase detector configured to receive a signal output from the binarizer and a signal fed back from the divider, compare phases, and detect a phase deviation; A first voltage controlled oscillator for generating and outputting a signal corresponding to a phase deviation received from the first phase detector; And a divider which receives the output of the first voltage controlled oscillator and divides the output at an appropriate ratio. The method of claim 2, wherein the wobble sync signal generating means The presence or absence of a wobble signal output from the RF means is determined, and when the wobble signal is detected, the signal received from the first phase detector is output to the first voltage controlled oscillator. And a first compensating means for outputting a signal held by averaging the output of the first phase detector to the first voltage controlled oscillator. The method of claim 3, wherein the first compensation means A wobble detection unit for determining the presence or absence of a wobble signal output from the RF means, and generating and outputting a detection signal corresponding to the determination result; A first average value calculating and holding unit configured to receive an output of the first phase detector, calculate an average value, and hold the same; An optical disc reproducing system including a first selector for selecting one of the signals received from the first phase detector and the first average value calculating and holding unit and outputting the selected signal to the first voltage controlled oscillator according to the wobble detection signal applied from the wobble detection unit; Synchronizing signal generator. The method of claim 4, wherein the first selector When a signal indicating that the wobble signal is present from the wobble detection unit is applied, the signal received from the first phase detector is output to the first voltage controlled oscillator, and when the signal indicating that there is no wobble signal is applied, the first average value is calculated and A synchronization signal generator of an optical disc reproducing system for outputting a signal received from a hold unit to a first voltage controlled oscillator. 6. The apparatus as claimed in claim 5, wherein the section without the wobble signal is a header section of the optical disk. 6. The apparatus as claimed in claim 5, wherein the section without the wobble signal is a section with a defect of the optical disk. The method of claim 1, wherein the RF synchronization signal generating means A second phase detector for receiving a RF signal from the RF means and a signal fed back from a second voltage controlled oscillator, comparing phases, and detecting phase deviations; A frequency detector configured to receive the output of the wobble synchronous signal generating means and a signal fed back from the second voltage controlled oscillator, compare frequencies, and detect frequency deviations; An adder which adds and outputs a signal received from the frequency detector to a signal received from the second phase detector; Determining the presence or absence of a defect of the RF signal output from the RF means, and outputs a signal received from the adder if a defect section is not detected, and if the defect section is detected, the average of the output of the adder to hold the signal Third compensation means for outputting; A loop filter which receives the output of the third compensation means and removes and outputs unnecessary noise and high frequency components; And And a second voltage control generator which receives the output of the loop filter and generates and outputs a signal having a frequency and a phase corresponding thereto. The method of claim 8, wherein the RF synchronization signal generating means The presence or absence of an RF signal output from the RF means is determined, and in a section in which the RF signal is found, the signal received from the phase detector is selected and output to an adder, and when a blank section without an RF signal is detected, the blank section is detected. And second compensating means for outputting a signal held by averaging the output of the second phase detector to the adder. The method of claim 9, wherein the second compensation means A blank detection unit for determining the presence or absence of an RF signal output from the RF unit, and generating and outputting a detection signal corresponding to the determination result; A second average value calculating and holding unit configured to receive the output of the second phase detector, calculate an average value, and hold the average value; And And a second selector for selecting and outputting one of the signals received from the second phase detector and the second average value calculation and hold section, according to the detection signal applied from the blank detection section. . The method of claim 10, wherein the second selector If a signal indicating that the RF signal is a period from the blank detector is applied, the signal output from the second phase detector is output, and if a signal indicating that the blank period without the RF signal is received from the second average value calculation and hold unit A synchronization signal generator of an optical disc reproducing system for outputting a signal.

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