KR910002438Y1 - Detecting circuit of compact disk defects - Google Patents
Detecting circuit of compact disk defects Download PDFInfo
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- KR910002438Y1 KR910002438Y1 KR2019870023801U KR870023801U KR910002438Y1 KR 910002438 Y1 KR910002438 Y1 KR 910002438Y1 KR 2019870023801 U KR2019870023801 U KR 2019870023801U KR 870023801 U KR870023801 U KR 870023801U KR 910002438 Y1 KR910002438 Y1 KR 910002438Y1
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- resistor
- defect
- compact disc
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/10—Digital recording or reproducing
- G11B20/18—Error detection or correction; Testing, e.g. of drop-outs
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/10—Digital recording or reproducing
- G11B20/10009—Improvement or modification of read or write signals
- G11B20/10018—Improvement or modification of read or write signals analog processing for digital recording or reproduction
- G11B20/10027—Improvement or modification of read or write signals analog processing for digital recording or reproduction adjusting the signal strength during recording or reproduction, e.g. variable gain amplifiers
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B2220/00—Record carriers by type
- G11B2220/20—Disc-shaped record carriers
- G11B2220/25—Disc-shaped record carriers characterised in that the disc is based on a specific recording technology
- G11B2220/2537—Optical discs
- G11B2220/2545—CDs
Abstract
내용 없음.No content.
Description
제1도는 본 고안에 의한 회로도.1 is a circuit diagram according to the present invention.
제2도는 제1도의 각부에 있어서의 타이밍챠트.2 is a timing chart of each part of FIG.
제3도는 포커싱 에러신호 라인의 시정수변화를 나타낸도이다.3 is a diagram illustrating a time constant change of a focusing error signal line.
본 고안은 콤팩트 디스크상에서 발생할 결함을 검출하는 회로로서, 특히 검출된 결과에 의하여 포커싱 서보와 트랙킹 서보에 에러신호가 크게 발생했을 때에도 음의 건너뜀을 방지하기 위한 회로에 관한 것이다.The present invention relates to a circuit for detecting a defect that will occur on a compact disc, and more particularly, to a circuit for preventing a negative skip even when an error signal is generated largely in the focusing servo and the tracking servo by the detected result.
종래에 콤팩트 디스크에 손상(scretch)이나 큰 핀홀, 또는 지문 등에 의한 결함이 있는 경우, 재생중 그 부위가 재생될 때 포토픽업에서 반사된 레이저 빔이 스포트(spot)는 디스크상의 상기 결함부에 조사된 후 반사되는 반사광이 정확하게 반사되지 못하고 산란되어 반사하기 때문에 반사광 검출부(픽업)에서는 정상적인 반사광을 검출하지 못하여 재생시 재생음의 건너뜀 현상이 발생하게 된다.Conventionally, when a compact disc has a defect such as a scratch, a large pinhole, a fingerprint, or the like, when the portion is reproduced during reproduction, the spot of the laser beam reflected from the photo pickup is irradiated to the defect portion on the disc. After the reflection is reflected, the reflected light is not accurately reflected but scattered and reflected, so that the reflected light detector (pickup) does not detect the normal reflected light, and thus the playback sound skips.
이로 인하여 서보용 신호에도 이상에러 데이터가 발생하여 트랙킹서보계에 혼란이 발생하여 재생음의 건너뜀 현상이 주요인이 되고 있다.As a result, abnormal error data is also generated in the servo signal, which causes confusion in the tracking servo meter, and the skipping of the reproduction sound is a major factor.
본 고안은 상기 문제점을 해소하기 위하여 고안된 것으로서 이하 도면에 의하여 상세히 설명한다.The present invention is designed to solve the above problems will be described in detail by the following drawings.
본 고안은 결함부에서 발생하는 HF 신호의 누락(제2도 참조)을 검출하는 피이크-홀드회로와 이것을 이용하여 신호의 결함 즉 빠진부분에 해당하는 만큼의 펄스를 발생시켜주는 펄스 발생부와, 이 펄스폭을 제한하는 부분, 또 이 신호를 이용하여 트랙킹에러 신호가 빠진 부분만큼 끊어주는 트랙킹서보루우프 차단회로와 포커싱 에러신호가 빠진 부분만큼 저역게인을 증가시켜주는 레그회로를 구성하므로서 상기 결함에 의한 영향을 보상할수 있게 된다.The present invention provides a peak-hold circuit for detecting a missing HF signal (see FIG. 2) generated in a defective part, and a pulse generator for generating a pulse corresponding to a defective part of a signal, that is, a missing part using the same. This defect is formed by configuring a tracking servo loop cut-off circuit that limits the pulse width, and a part of the tracking error signal missing by using this signal, and a leg circuit that increases the low-pass gain by the part missing the focusing error signal. It will be able to compensate for the effects.
본 고안에 의한 회로의 구성을 설명한다.The structure of the circuit by this invention is demonstrated.
제1도에 나타낸 바와 같이 HF 신호는 A에서 트랜지스터(Q1)의 베이스에 입력된다. 그 출력은 트랜지스터(Q2)의 베이스를 거쳐 부전위(-Vcc)에 저항(R3)과 콘덴서(C1)가 병렬접속된 피이크홀드부(1)에 접속되고, 트랜지스터(Q2)와 상기 피이크 홀드부 즉 저항(R3), 콘덴서(C1)의 공통접속부(B)에 차동증폭기(IC1)가 접속된다. 단 차동증폭기(IC1)의 반전 입력단자에는 상기 접속점(B)으로부터 콘덴서(C2)를 거쳐 전원(Vcc)에 접속된 저항(R4)과의 접속점(D)이 연결되고 비반전 입력단자에는 다이오드(D1)을 거쳐 입력된다. 상기 차동증폭기(IC1)의 두 입력단간에는 다이오드(D2)와 저항(R5)이 직렬접속되어 있다.As shown in FIG. 1, the HF signal is input at A to the base of the transistor Q1. The output is connected to the peak hold portion 1 in which the resistor R3 and the capacitor C1 are connected in parallel to the negative potential (-V cc ) through the base of the transistor Q2, and the transistor Q2 and the peak hold are connected. That is, the differential amplifier IC1 is connected to the common connection portion B of the resistor R3 and the capacitor C1. However the inverted input terminal of the differential amplifier (IC1), the connection point (D) of a resistor (R4) connected to a power supply (V cc) via a capacitor (C2) from the connection point (B) connected and a non-inverting input terminal of the diode It is input via (D1). A diode D2 and a resistor R5 are connected in series between two input terminals of the differential amplifier IC1.
상기 저항(R5)과 상기 다이오드(D1)의 캐소드측 접점(C)과 접지간에는 저항(R6), 콘덴서(C3)가 병렬로 접속되어 있다. 상기 차동증폭기(IC1)의 출력단(E)으로부터의 출력은 트랙킹에러 전송라인(트릭킹서보루우프)에 콜렉터가 접속된 트랜지스터(Q3)의 베이스에 저항(R7)을 거쳐 입력됨과 동시에, 마찬가지로 포커싱 에러신호 전송라인(포커싱서보루우프)에 콜렉터가 접속된 트랜지스터(Q4)의 베이스에 저항(R8)을 거쳐 접속되어 있다. 상기 트랜지스터(Q4)의 콜렉터에는 콘덴서(C6)와 저항(R9)으로 된 래그회로가 접속되어 있다.A resistor R6 and a capacitor C3 are connected in parallel between the resistor R5, the cathode side contact C of the diode D1, and the ground. The output from the output terminal E of the differential amplifier IC1 is input to the base of the transistor Q3 connected to the tracking error transmission line (tricking servo loop) via the resistor R7 and at the same time a focusing error. The base of transistor Q4 is connected to a signal transmission line (focusing servo loop) via a resistor R8. A lag circuit composed of a capacitor C6 and a resistor R9 is connected to the collector of the transistor Q4.
이상과 같이 구성된 본 고안의 동작을 설명하면 다음과 같다. 먼저 콤팩트 디스트 플레이어 동작중 디스크상에 위에서 설명한 바와 같은 결함부위가 있을 때 이로인한 재생출력 즉 HF 신호중에는 제2도 A에 나타낸 바와같이 HF 신호의 누락부분이 발생한다. 이 신호는 트랜지스터(Q1, Q2) 및 저항(R3), 콘덴서(C1)에서 피이크 홀드되어 제2도 B에 나타낸 바와 같이 된다.Referring to the operation of the present invention configured as described above are as follows. First, when there is a defect portion as described above on the disc during the operation of the compact disc player, a missing portion of the HF signal occurs as shown in FIG. This signal is peak held in transistors Q1 and Q2, resistor R3 and capacitor C1, as shown in FIG.
상기 피이크홀드가 된 신호는 다이오드(D1), 저항(R6)과 콘덴서(C3)로 구성된 회로에서 평활된 직류성분으로 변환되어 차동증폭기(IC1)의 비반단에 입력된다. 이때 콘덴서(C3)의 용량치는 입력신호에 적합하도록 적절히 선정된다. 한편 피이크-홀드된 신호는 도면중 B점에 접속된 콘덴서(C2)를 거쳐 DC 레벨이 저하(down)되고 저항(R4)에 의해 바이어스 되어 차동증폭기(IC1)의 반전입력단에 입력된다. 이때 차동증폭기(IC1)의 양입력단사이에 직렬접속된 다이오드(D2), 저항(R5)에 의하여 접속점(C)의 DC 레벨은 접속점(D)의 레벨보다 대략 0.6V 정도 낮은 레벨이 유지된다. 단, HF 신호가 빠지는 부분에서는 접속점(C)의 레벨이 접속점(D)의 레벨보다 높아지므로 (제2도 C, D 참조) 차동증폭기(IC1)의 출력은 신호가 빠지기 시작하는 부분에서 약 0.6V 낮은 곳(제2도 C, D의 점선으로 표시한 부분)에 대응되는 부분부터 반전된다(제1도 E 참조).The peaked signal is converted into a smooth DC component in a circuit composed of a diode D1, a resistor R6, and a capacitor C3, and is input to the non-end of the differential amplifier IC1. At this time, the capacitance of the capacitor C3 is appropriately selected to suit the input signal. On the other hand, the peak-held signal is inputted to the inverting input terminal of the differential amplifier IC1 via the capacitor C2 connected to point B in the figure, the DC level is lowered and biased by the resistor R4. At this time, the DC level of the connection point C is maintained about 0.6V lower than the level of the connection point D by the diode D2 and the resistor R5 connected in series between the two input terminals of the differential amplifier IC1. However, since the level of the connection point C is higher than the level of the connection point D at the portion where the HF signal is missing (see FIGS. 2 and 4), the output of the differential amplifier IC1 is about 0.6 at the portion where the signal starts to be dropped. It is inverted from the portion corresponding to the lower V (parts indicated by the dotted lines in Figs. C and D in Fig. 2) (see Fig. 1E).
트랙킹서보를 행하게 될때, 트랜지스터(Q3)와 저항(R3)으로 이루어진 차단회로는 차단증폭기(IC1)의 출력신호(E)에 의하여 디스크상에서 결함이 발생되면, 트랙킹 에러신호로서 이를 검출하여 트랙킹 제어 루우프가 결함부분의 에러성분에 응답하는 것을 방지하므로서 결함 발생부분에서 음 건너뜀을 방지하는 것이다.When the tracking servo is performed, a blocking circuit composed of the transistor Q3 and the resistor R3 detects a defect on the disk by the output signal E of the blocking amplifier IC1 and detects it as a tracking error signal to detect the tracking control loop. This function prevents the sound skipping at the defect generation part by preventing the response of the error component of the defect part.
또한, 저항(R8, R9, R10), 캐패시터(C6), 트랜디스터(Q4)로 구성된 레그회로부는 디스크상에서 결함이 발생시 차동증폭기(IC1)의 출력신호(E)에 의하여 고역(high frequency) 노이즈를 차단하여 결함에 의해 발생된 에러 성분이 포커싱 엑추에이터에 인가되지 않게 한다.In addition, the leg circuit portion composed of resistors R8, R9, R10, capacitor C6, and transistor Q4 generates high frequency noise by the output signal E of the differential amplifier IC1 when a defect occurs on the disk. Block the error component caused by the defect from being applied to the focusing actuator.
제3도에 도시된 바와 같이 래그회로는 HF 신호가 빠져서 트랜지스터(Q4)가 온되면 시정수가 변화하여 저항(R10)과 캐패시터(C6)로 구성되는 1차 로우패스필터(LPF)를 형성하여 고역 노이즈를 차단하고, 저역부게인을 상승시켜 주므로 HF 신호가 빠져셔 재새음이 건너뛰는 경우에도 용이하게 포커싱서보를 유지제어할 수 있게 된다. 트랜지스터(Q4)가 오프되는 경우 저항(R9)은 매우 큰 저항값(수백 K Ω)을 가지고 있으므로 서보 대역내에서는 평탄한 주파수 특성을 가진다.As shown in FIG. 3, when the transistor Q4 is turned on because the HF signal is omitted, the lag circuit changes the time constant to form a primary low pass filter LPF composed of a resistor R10 and a capacitor C6, thereby forming a high frequency band. Since the noise is cut off and the low-pass gain is increased, the focusing servo can be easily maintained even in the case where the HF signal is lost and the resounding is skipped. When the transistor Q4 is turned off, the resistor R9 has a very large resistance value (hundreds of K kHz) and thus has a flat frequency characteristic in the servo band.
이상 설명한 바와 같이 본 고안을 콤팩트 디스크 플레이어에 적용함으로써 디스크에 결함부분이 생겨 신호가 누락되므로서 발생하는 포커싱 및 트랙킹 서보의 불안요인을 제거할 수가 있어 재생시 디스크의 결함부위에서의 음의 건너뜀을 방지할 수 있는 효과가 있다.As described above, by applying the present invention to a compact disc player, it is possible to eliminate anxiety factors of focusing and tracking servos caused by missing signals due to defects in the discs, so that the sound skips on the defective parts of the discs during playback. There is an effect that can prevent.
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KR2019870023801U KR910002438Y1 (en) | 1987-12-30 | 1987-12-30 | Detecting circuit of compact disk defects |
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KR2019870023801U KR910002438Y1 (en) | 1987-12-30 | 1987-12-30 | Detecting circuit of compact disk defects |
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KR910002438Y1 true KR910002438Y1 (en) | 1991-04-20 |
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