KR100333334B1 - Apparatus for Reproducing Signal Amplitude Level and Disc Drive System Including It - Google Patents

Abstract

end. TECHNICAL FIELD This invention relates to a disk drive system.

I. SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a reproduction signal amplitude level detection device capable of accurately detecting an amplitude level of a reproduction signal using only a simple hardware configuration.

All. SUMMARY OF THE INVENTION A data converter for converting and outputting an amplitude level of an analog signal reproduced from a recording medium surface into digital data, and having a different level by comparing an amplitude level output from the converter with a preset threshold value. A primary level detector for outputting valid data and level retention data of another level, a first memory for temporarily storing signal string data consisting of the valid data and level retention data, and determining the level retention data in the primary level detector A second memory for storing the amplitude level value of the digital data, a period detector for counting and outputting a predetermined pulse period among the signal string data input from the first memory, and a pulse period counting data input from the period detector. Search and output the signal string data output from the first memory. And it characterized in that it consists of the second level detector that determines a pulse period based on the level attribute level reservation data so that it is acceptable for the reproduction signal.

la. Important uses of the invention: It can be used in disc drive systems such as DVD-RAM, DVD-ROM drive, HDD.

Description

Apparatus for Reproducing Signal Amplitude Level and Disc Drive System Including It

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to data restoration of a disc drive system, and more particularly, to an apparatus for accurately detecting the amplitude level of a reproduction signal in consideration of the pulse period characteristic of the reproduction signal, and a disc drive system including the same.

Disc drive systems such as DVD-ROM (Digital Versatile Disc-ROM), DVD-RAM (RAM), CD-R / W (ReWritable) drives, and hard disk drives are examples of data storage devices in the spotlight today. . The above-described disc drive system includes a read channel circuit for amplifying and waveform equalizing before converting a signal reproduced from the disc surface, and converting the digital data into output. In such a read channel circuit, the pulse period T of the reproduction signal is detected by comparing the amplitude level of the reproduction signal with a preset threshold.

Specifically, FIG. 1 shows a signal waveform diagram for explaining a reproduction signal amplitude level detection method employed in a general optical disk drive system. In FIG. 1, the first threshold value and the second threshold value are preset values for detecting the pulse period T of the reproduction signal. As shown, when the amplitude level of the reproduction signal exceeds the first threshold value, the pulse period T maintains the "high" level, and when the amplitude level of the reproduction signal is less than the second threshold value, the "low" level is maintained. However, if the amplitude level of the reproduction signal exists between the first threshold value and the second threshold value, the pulse periods 3T to 11T / 14T cannot be detected because the pulse period T may not be reversed at any point. This immediately acts as a factor to lower the reliability of the pulse period detection of the reproduction signal.

Fig. 2 shows an example of waveforms of an ideal output waveform ② and a signal ③ distorted by signal interference in the optical disk drive system. In general, in a high-speed disk drive system, when a long period signal is followed immediately by a short period signal such as 3T or 4T, the short period signal tends to be shorter even under the influence of the long period signal. Therefore, the signal of 4T may be mistaken for the signal of 3T, and the signal of 3T may be mistaken for the signal of 2T which does not match the characteristics of the optical disk. Therefore, if the above-described reproduction signal amplitude level detection method is used, no action can be taken.

On the other hand, the Viterbi decoding algorithm has been introduced as a method for improving the reliability of detecting the pulse period of the reproduction signal. In order to implement the Viterbi decoding algorithm, complex hardware must be provided, and hardware There is a disadvantage to satisfy the operating speed.

Accordingly, an object of the present invention is to provide a reproduction signal amplitude level detection device capable of accurately detecting the amplitude level of a reproduction signal with a simple hardware configuration.

It is still another object of the present invention to provide a reproducing signal amplitude level detecting apparatus capable of reducing the amplitude level detection error of a signal reproduced from a recording medium such as a magnetic disk or an optical disk, and a disk drive system including the same.

In order to achieve the above object, the present invention provides an apparatus for detecting an amplitude level of a signal reproduced from a recording medium.

A data converter which converts and outputs the amplitude level of the analog signal reproduced from the recording medium surface into digital data;

A primary level detector for outputting valid data having different levels and level retention data of another level by comparing the amplitude level output from the converter with a preset threshold value;

A first memory for temporarily storing signal string data consisting of the valid data and the level reservation data;

A second memory for storing an amplitude level value of digital data determined as level reservation data in the primary level detector;

A period detector for counting and outputting a pulse period of a predetermined level among the signal string data input from the first memory;

And a second level detector for retrieving the pulse period counting data input from the period detector and determining the level of the level reservation data so that the signal string data output from the first memory conforms to the pulse period characteristics of the reproduction signal. It features.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a signal waveform diagram for explaining a reproduction signal amplitude level detection method employed in a general optical disc drive system.

2 is an exemplary waveform diagram of a signal that is distorted by an ideal output waveform and signal interference in an optical disk drive system.

3 is a block diagram of a playback signal amplitude level detection device according to an embodiment of the present invention;

4 is a diagram illustrating signal transmission and reception between a periodic detector 500 and a second level detector 600 in FIG. 3.

FIG. 5 is an exemplary data diagram illustrating output data types of the primary level detector 200 and the secondary level detector 600 in FIG. 2.

FIG. 6 is a diagram illustrating data for explaining a process of outputting data in a direction of generating a minimum error using a digital level stored in the memory 300 of FIG. 2.

Hereinafter, an operation according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram of an apparatus for detecting an amplitude level of a reproduced signal according to an exemplary embodiment of the present invention, which is located between an optical pickup in an optical disk drive system and a DSP (Digital Signal Processor), which is a data processor. . In addition, it is assumed that each unit of the reproduction signal amplitude level detecting apparatus according to the embodiment of the present invention operates in synchronization with the system clock.

Referring to FIG. 3, the A / D converter 100 converts the amplitude level of the analog signal reproduced from the optical disk surface into digital data through an optical pickup (not shown). The primary level detector 200 compares the amplitude level output from the A / D converter 100 with a preset first threshold value or a second threshold value and has valid levels and level reservation data (“X”) having different levels. Will output That is, the first level detector 200 outputs valid data “1” when the amplitude level converted into digital data exceeds the first threshold value as shown in FIGS. 5 and 6, and the amplitude level is the second threshold value. If exceeded, valid data "0" is output. The primary level detector 200 outputs level reservation data of "X" when the amplitude level has a value between the first threshold value and the second threshold value. The meaning of the level reserved data refers to data whose level is not specified.

On the other hand, the memory 300 stores the amplitude level value output from the primary level detector 200, wherein the amplitude level value to be stored is stored in the digital data determined as the level reservation data in the primary level detector 200. The amplitude level value.

The first-in first-out (FIFO) memory 400 temporarily stores signal string data composed of valid data and level reservation data output from the first-level detector 200, and then the second-level detector 600 by the first-in first-out method. And to the period detector 500.

The period detector 500 counts and outputs a valid data string of a predetermined level ("0" or "1") from the signal string data input from the covered memory 400 until the level reservation data "X" is input. Pulse period T is detected. That is, the period detector 500 counts and outputs a pulse period T among the signal string data.

The secondary level detector 600 retrieves the pulse period T counting data input from the period detector 500 when the level reservation data (X) is input from the covered memory 400, thereby pulses of the optical disk reproduction signal. The level holding data "X" is set to a certain level ("0" or "1") and outputted in accordance with the periodic characteristics. If the pulse period characteristic of the optical disk reproducing signal is satisfied as a result of retrieving the pulse period T counting data, the secondary level detector 600 uses the amplitude level value stored in the memory 300 to display the level reservation data ("). Determine the level of X ") as the minimum level of error.

4 illustrates an example of signal transmission and reception between the periodic detector 500 and the secondary level detector 600 in FIG. 3, and FIG. 5 illustrates the primary level detector 200 and the secondary level detector (FIG. 3). FIG. 6 is a diagram illustrating a data for explaining an output data form of FIG. 6, and FIG. 6 illustrates a process in which data is output in a direction of generating a minimum error using a digital level stored in the memory 300 of FIG. 3. Figures for illustrating the data for each is shown. 5 and 6, 200 and 600 show output data of the primary level detector 200 and the secondary level detector 600, respectively.

If the analog signal reproduced from the optical disk surface is input to the A / D converter 100 and converted into digital data having an amplitude level as shown in Fig. 5, the digital data having such an amplitude level is a primary level. The detector 200 outputs signal string data having the same level as "X, 0, O, X, 1, 1, X, 0". That is, in the primary level detector 200, when the amplitude level input from the A / D converter 100 is larger than the preset first threshold value, valid data having a "1" level is output, and the amplitude smaller than the second threshold value. When the level is input, valid data having a "0" level is output, while when the amplitude level existing between the first threshold value and the second threshold value is input, the level reservation data having the "X" level is shown in FIG. As shown in FIG. As such, the signal string data including the valid data and the level reservation data is sequentially input to the PIO memory 400 in synchronization with the system clock and output in a first-in first-out manner. Therefore, the period detector 500 counts and outputs a pulse period T of valid data having a level of "0" or "1" among the signal string data input from the PPI memory 400. If the signal string data output from the secondary level detector 600 before the third level reservation data input is "1,0,0" as shown in FIG. 5, the pulse period counting data up to now is 2T. Accordingly, in the second level detector 600, the pulse period counting data 2T input from the period detector 500 at the time of the third level reservation data input is the pulse period characteristics (3T to 11T / 14T) of the optical disk reproduction signal. Check if it has a value satisfying If the inspection results do not satisfy the pulse period characteristic, the level reservation data ("X") is determined as "0" level and outputted to satisfy the pulse period characteristic of the optical disk reproduction signal.

Meanwhile, referring to FIG. 6, signal string data output from the primary level detector 200 is represented by “0,0,0, X, 1,1,1, X”. In this case, the period detector 500 outputs 3T pulse period counting data. Therefore, since the pulse period characteristic of the optical disk reproducing signal is satisfied, the amplitude level value stored in the memory 300 is used to determine the level to minimize the error. That is, the secondary level detector 600 outputs the level of the level reservation data input as "0" when the amplitude level value output from the memory 300 is close to the first threshold value, and inputs when the amplitude level value is close to the first threshold value. The level reservation data is determined as "1" and output. Therefore, the fourth level reservation data "X" shown in FIG. 6 has a "1" level.

Accordingly, the present invention enables to accurately detect the amplitude level of the reproduction signal existing between the preset thresholds as illustrated in FIGS. 5 and 6.

In the embodiment of the present invention, the optical disk has been described as an example, but the present invention can be applied to a disk drive system using a hard disk as a recording medium without any modification. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be defined by the claims and their equivalents.

As described above, the present invention can accurately detect the amplitude level of the reproduction signal existing between preset threshold values, thereby reducing the number of pulse period detection errors of the reproduction signal, and implementing the Viterbi decoding algorithm. There is an advantage that can simplify the configuration of the hardware.

Claims (6)

An apparatus for detecting an amplitude level of a signal reproduced from a recording medium, A data converter which converts and outputs the amplitude level of the analog signal reproduced from the recording medium surface into digital data; A primary level detector for outputting valid data having different levels and level retention data of another level by comparing the amplitude level output from the converter with a preset threshold value; A first memory for temporarily storing signal string data consisting of the valid data and the level reservation data; A second memory for storing an amplitude level value of digital data determined as level reservation data in the primary level detector; A period detector for counting and outputting a pulse period of a predetermined level among the signal string data input from the first memory; And a second level detector for retrieving the pulse period counting data input from the period detector and determining the level of the level reservation data so that the signal string data output from the first memory conforms to the pulse period characteristics of the reproduction signal. A reproducing signal amplitude level detecting device, characterized in that. The method of claim 1, wherein the secondary level detector; When the pulse period counting data search result satisfies the pulse period characteristic of the reproduction signal, the reproduction signal amplitude level detection is performed by determining the level of the input level reservation data using the amplitude level value stored in the second memory. Device. The apparatus of claim 1, wherein the first memory is a FIFO memory. A disc drive system comprising a disc on which data is recorded, and a lead channel circuit for amplifying and waveform equalizing a signal reproduced from the disc through pickup and converting the signal into digital data. A data converter which converts and outputs the amplitude level of the analog signal reproduced from the disk into digital data; A primary level detector for outputting valid data having different levels and level retention data of another level by comparing the amplitude level output from the converter with a preset threshold value; A first memory for temporarily storing signal string data consisting of the valid data and the level reservation data; A second memory for storing an amplitude level value of digital data determined as level reservation data in the primary level detector; A period detector for counting and outputting a pulse period of a predetermined level among the signal string data input from the first memory; A second level detector for retrieving pulse period counting data input from the period detector and determining a level of level reservation data so that the signal string data output from the first memory conforms to a pulse period characteristic of the reproduction signal; At least in the circuitry. 5. The disk drive system according to claim 4, wherein the disk is an optical disk. 5. The disk drive system according to claim 4, wherein the disk is a magnetic disk.