KR900006583B1 - Recording data reproducing circuit and compensating method of error for pit position recording method - Google Patents

Abstract

The circuit for reproducing the data recorded by pit position method comprises a differential circuit (2) differentiating the reproducing signal of the pit recorded on an optical disc (6), a pulse generator (3) detecting the data with tangent and level of the differentiated signal, a comparator (4) providing pulse signal by comparing the reproducing signal to the reference voltage (Vref), and a delay circuit (5) compensating the delayed time of the reproducing signal of the differential circuit.

Description

Record data reproducing circuit of pit position recording method, and reproducing error correction method

1 is an explanatory diagram showing a relationship of recording data on an optical disc in a pit position recording method.

2 is an explanatory diagram showing a relationship of reproducing data recorded by a pit position recording system by a differential detection method.

3 is an explanatory diagram showing a malfunction of the binary detection method.

4 shows an embodiment of a reproduction circuit of the present invention.

5 is a waveform diagram of each part of FIG.

* Explanation of symbols for main parts of the drawings

1: Signal generating unit 2: Differential unit

3: Pulse generator 4: Comparator

5: delay unit 6: optical disc

8: optical pickup unit Vref: reference voltage

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording data reproducing circuit of a pit position recording method and a reproducing error correction method for reproducing data recorded in a pit position recording method on an optical disc without errors. As shown in Fig. 1, the pit position recording method encodes data to be recorded with a constant pulse signal width and a different position, and scans a recording optical pulse onto an optical disc according to the encoded recording data to thereby record each bit of the recording data. This is a method of recording so that the center position of the recording pitch corresponds to the value “1” As a method of reproducing data recorded on an optical disc by such a pit position recording method, an amplitude detection method and a differential detection method have been known.

In the amplitude detection method, the reproduction signal picked up by the optical pickup unit is directly divided into a constant value on the optical disc, and the maximum value is detected to reproduce the data. However, the amplitude detection method has a problem in that data cannot be accurately detected due to the reduction of the amplitude of the reproduction signal due to the interference of adjacent recording feet, and there are many problems.

In the differential detection method, as shown in FIG. 2, the optical pickup unit picks up and outputs the recording pits recorded on the optical disc, and outputs the derivatives. The derivative signal has a constant value A and the level is " 0 " The data is reproduced using the view point. Since the differential detection method reproduces data by directly detecting the slope of the differential signal that differentiates the reproduction signal from the amplitude of the reproduction signal with respect to the recording feet, the effect of the amplitude reduction of the reproduction signal due to the interference of adjacent recording feet. There is an advantage of receiving very little. However, while the differential detection method is less affected by the amplitude of the reproduction signal due to the interference of adjacent recording feet, the amplitude of the amplitude detection method is increased because the data is reproduced using the slope of the differential signal that differentiates the reproduction signal. In the differential detection method, a small neglected noise signal has a problem of incorrect reproduction of data. That is, as shown in FIG. 3, in the amplitude detection method, when a noise signal whose amplitude is small is mixed into a reproduction signal and differentiates it, a noise signal having a small amplitude is also differentiated by a certain slope. Since there is a problem that the noise signal is reproduced incorrectly as data. It is therefore an object of the present invention to provide a reproducing circuit and a reproducing error method for accurately reproducing data in a reproducing signal by using the above differential detection method.

The present invention having the above object differentiates the reproduction signal of the recording feet, and compares the reproduction signal with the reference voltage to remove the noise signal, delays the comparison signal for a predetermined time, and differentiates the reproduction signal of the recording feet. This is achieved by synchronizing with and reproducing the data with the slope of the differential signal of the reproduction signal according to the comparison signal delayed for a certain time.

Hereinafter, with reference to the accompanying drawings 4 and 5 showing a preferred embodiment of the present invention will be described in detail.

4 is a detailed view showing an embodiment of the reproducing circuit of the present invention, and as shown therein, an optical pickup section 8 for picking up the recording pitch recorded on the optical disc 6 which is rotated in accordance with the driving of the motor 7; A signal reproducing unit 1 for reproducing the signal of the optical pickup unit 8, a differential unit 2 for differentiating the reproducing signal of the signal reproducing unit 1, and an output of the comparing unit 4; A delay unit 5 for delaying a signal and synchronizing with a differential signal of a reproduction signal output from the derivative unit 2, and operated according to an output signal of the delay unit 5 to output the derivative unit 2; It consists of the pulse generator 3 which detects data from a differential signal.

According to the present invention configured as described above, the optical disk 6 is rotated in accordance with the driving of the motor 7, and the recording pitch recorded by scanning the recording light pulse on the optical disk 6 in accordance with the recording data as shown in FIG. The optical pickup unit 8 picks up the signal, and the signal reproducing unit 1 reproduces the picked-up signal and outputs a reproduction signal as shown in FIG.

In this way, the reproduction signal output from the signal reproducing unit 1 is inputted to the differential unit 2, differentiated as shown in FIG. 5 (b), and inputted to the comparing unit 4, so that the comparison unit 4 is a signal reproducing unit. The reproduction signal output by (1) is compared with the reference voltage Vref. When the reproduction signal is larger than the reference voltage Vref as shown in (c) of FIG. 5, the logic is "0" and the reproduction signal is the reference voltage Vref. If smaller, output a pulse signal of logic “1”, that is, output a pulse signal unaffected by noise signals with small amplitude.

In this way, the pulse signal output from the comparator 4 compensates for a predetermined time delayed by the derivative 5 from the delay unit 5, and the delayed pulse signal is input to the pulse generator 3 as an operation signal.

Therefore, the pulse generator 3 operates normally only when the pulse signal output from the delay unit 5 is a logic "1", and the slope of the derivative signal output from the derivative unit 2 is A 'and the level is " The point of time 0 ”is detected and only pure data is output without affecting the noise signal as shown in FIG.

That is, when the noise signal mixed in the reproduction signal is differentiated in the derivative section 2, it appears as a differential signal having a constant slope A 'and a level of 0, but the level of the noise signal mixed in the reproduction signal is Since the comparator 4 outputs a pulse signal having no influence on the noise signal because it is larger than the reference voltage Vref, the pulse generator 5 operates according to the delay signal of the pulse signal and is mixed in the reproduction signal. The error caused by the signal is corrected and only the data is output.

As described in detail above, the present invention has the effect of removing the noise signal in the reproduction signal of the recording pitch recorded on the optical disc and accurately reproducing the data.

Claims (2)

A pit having a differential unit 2 for differentiating a reproduction signal of a recording pit recorded on the optical disc 6, and a pulse generator 3 for detecting and outputting data at a slope and level of the differential signal of the differential unit 2; A recording data reproducing circuit of a position recording method, comprising: a comparison unit (4) for generating a pulse signal without influence of a noise signal by comparing a reproducing signal of the recording pit with a predetermined reference voltage (Vref) previously set; And a delay unit 5 for delaying the output signal of the unit 4 to compensate for the delay time of the reproduction signal in the derivative unit 2 and outputting the operation signal to the pulse generator 3 as an operation signal. A recording data reproducing circuit according to a pit position recording method. A method of differentiating a reproduction signal of a recording pit of an optical disc and reproducing data at a slope and level of the differential signal, wherein the reproduction signal of the recording pit is compared with a preset reference voltage to obtain a pulse signal without the influence of a noise signal. A pit position type recording data reproduction error, characterized in that the generated pulse signal is delayed for a predetermined time to synchronize with the differential signal of the reproduction signal and the data is reproduced at the slope and level of the differential signal according to the delayed pulse signal. Correction method.

Images