JP3678300B2 - Disc data continuous point detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, when the servo system of the optical pickup is disconnected, the continuous point detection of the disk data for detecting the continuous point of the data stored in the memory before the disconnection and the data read by returning to the position where the optical pickup is disconnected Relates to the device.
[0002]
[Prior art]
In general, as a function of a disc playback player, a shock proof function is known in order to prevent normal playback from being disabled when a servo system such as a focus servo or tracking servo of an optical pickup is disconnected due to an impact. The shock proof function of CD (compact disc) was introduced after the announcement of MD (mini disc), but MD was originally developed with shock proof in mind, whereas the format of CD was originally Not suitable for shockproof.
[0003]
The reason for this will be described. First, both CD and MD data are in units of one symbol (= 1 byte = 8 bits). As shown in FIG. 4, the minimum EFM frame is a synchronization signal, a subcode, It is composed of 12 symbol data, 4 symbol C2 parity, 12 symbol data, and 4 symbol C1 parity. The main data is composed of 12 × 2 symbol data and 4 × 2 symbol C2 and C1 parity.
[0004]
Both the CD and MD formats are composed of 98 frames as shown in FIGS. 5 (a) and 5 (b). The CD subcode is composed of 8-bit P, Q, R, S, T, U, V, and W subcodes. Each subcode is composed of 98 frames to form one frame (= 98 bits). doing. Among them, the Q code frame indicates an address, and in MD, the address is included in the main data.
[0005]
Here, since the parity for C2 and C1 correction is included in the main data, the error of the data read from the disk can be corrected based on the C2 and C1 parity. Therefore, the MD can correct an error in the address in the main data. However, in the CD format, the Q code frame indicating the address is not included in the main data, and although a CRC is added, this only detects an error and cannot be corrected. You may think that it has occurred. Therefore, since the subcode and the main data have a large difference in reliability, the CD and MD addresses also have a large difference in reliability. In addition, the CD subcode is provided with only one address for 98 EFM frames (= 1 subcode frame).
[0006]
For this reason, in order to realize the shock proof function of CD, as shown in FIG. 6, the servo system comes off at the point P due to the impact while the pickup is reproducing spirally from the inner periphery to the outer periphery, and then When returning to a location backward from point P, the data normally stored in the memory up to point P is compared with the data read from the CD after returning, and if they match, the point is determined to be continuous data. Thus, the read data after point P is stored in the memory.
[0007]
[Problems to be solved by the invention]
By the way, the data normally stored in the memory up to the point P and the data to be compared read from the CD after the servo return are both interpolated if error correction cannot be performed, and therefore coincides with each other. There is a problem that the probability of not performing is high and the detection probability is low.
[0008]
In view of the above-described conventional problems, the present invention provides a continuous point between data stored in a memory before disconnecting and data read after returning from the position where the optical pickup is disconnected when the servo system of the optical pickup is disconnected. An object of the present invention is to provide a disc data continuity detecting device capable of improving the probability of detecting the disc data.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention interpolates the data stored in the memory when comparing the data read from the disk with the data stored in the memory when the servo is restored after the servo is released. If it is, it is determined that they match.
That is, according to the present invention, when the data read from the disk is error-corrected and the error cannot be corrected, the disk signal that interpolates and outputs and outputs an interpolation flag indicating whether or not the interpolation is performed. A processing circuit;
Storage means for storing data output from the disk signal processing circuit and an interpolation flag;
When comparing the plurality of word data output from the disk signal processing circuit and the plurality of word data stored in the storage means when returning after the servo is released, the data side stored in the storage means When the interpolation flag added to each word is considered to be a match, it outputs a continuous point detection signal, and when the interpolation flag is off, a continuous point detection signal is output when the comparison results match. Data comparison means to
An apparatus for detecting a continuous point of disc data is provided.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a disc data continuation point detecting apparatus according to the present invention, FIG. 2 is an explanatory diagram showing data to be compared by the data comparison block of FIG. 1, and FIG. It is a block diagram which shows a data comparison block in detail.
[0011]
In FIG. 1, CD 1 is rotated at CLV by a spindle motor (M) 2, and pit data recorded on CD 1 is read by an optical pickup 3. This read signal is subjected to processing such as EFM demodulation, deinterleaving, error correction, interpolation and subcode decoding by the CD signal processing IC 4, and audio PCM data in which one word is 16 bits is stored in the DRAM 5. At this time, the CD signal processing IC 4 performs C1 and C2 series error correction, and generates a 1-bit interpolation flag indicating whether or not interpolation has been performed for each word. This interpolation flag is also stored in the DRAM 5 in the same manner.
[0012]
In such a configuration, in order to realize the shock proof function of the CD, as shown in FIG. 6, the servo system comes off at the point P due to an impact while the pickup is reproducing spirally from the inner periphery to the outer periphery, and then When returning to a location backward from the P point, 16-bit × 8-word data (hereinafter referred to as memory data) and an 8-word interpolation flag (hereinafter referred to as memory interpolation flag) normally stored in the memory up to the P point are stored. Read from the DRAM 5, the memory data and the memory interpolation flag are converted into bit serial data by the P → S converters 6 a and 6 b, respectively, and then transferred to the data comparison block 7. Similarly, the comparison target data read from the CD after the servo return and the interpolation flag are transferred from the CD signal processing IC 4 to the data comparison block 7. The shock proof processing IC 8 is constituted by a DSP (digital signal processor) including the P → S converters 6 a and 6 b and the data comparison block 7.
[0013]
The upper part of FIG. 2 shows 16-bit data of word A as data (disc reproduction data) D for 8 words A to H reproduced from the disc and transferred from the CD signal processing IC 4 and each flag (disc reproduction data interpolation flag) C2D. AD _{0 to} AD ₁₅ and flag C2DA
16-bit data BD _{0 to} BD _{15 of} word B and flag C2DB
16 bit data CD _{0 to} CD _{15 of} word C and flag C2DC
16-bit data DD _{0 to} DD _{15 of} word D and flag C2DD
16-bit data ED _{0 to} ED _{15 of} word E and flag C2DE
16-bit data FD _{0 to} FD _{15 of} word F and flag C2DF
16-bit data GD _{0 to} GD _{15 of} word G and flag C2DG
16-bit data HD _{0 to} HD _{15 of} word H and flag C2DH
Is shown.
[0014]
Further, the lower stage shows data (memory data) M corresponding to 8 words A to H taken out from the DRAM 5 and each flag (memory data interpolation flag) C2M as 16-bit data AM _{0 to} AM ₁₅ of the word A and a flag C2MA.
16-bit data BM _{0 to} BM _{15 of} word B and flag C2MB
16-bit data CM _{0 to} CM _{15 of} word C and flag C2MC
16-bit data DM _{0 to} DM _{15 of} word D and flag C2MD
16-bit data EM _{0 to} EM _{15 of} word E and flag C2ME
16-bit data FM _{0 to} FM _{15 of} word F and flag C2MF
16-bit data GM _{0 to} GM _{15 of} word G and flag C2MG
16-bit data HM _{0 to} HM _{15 of} word H and flag C2MH
Is shown.
[0015]
In the data comparison block 7, as shown in FIG. 3, E-OR gates 10 are provided for 16 (bits) × 8 (words), each of which has 16 × 8 bits of disk reproduction data D and memory data M. Data is applied. The inverted output signal of the E-OR gate 10 is applied to the AND gates 11A to 11H for each of the words A to H. Therefore, the AND gates 11A to 11H have 16 of the disk reproduction data D and the memory data M for each of the words A to H. When all the bits match, “1” is output to one input terminal of the OR gates 12A to 12H.
[0016]
Memory data interpolation flags C2MA to C2MH of the words A to H are applied to the other input terminals of the OR gates 12A to 12H, respectively. Therefore, the OR gates 12A to 12H have the memory data interpolation flags C2MA to C2MH set to “1”, respectively. ", That is, when the memory data M for each of the words A to H is interpolated," 1 "is output even if the 16 bits of the disc reproduction data D and the memory data M do not all match. The subsequent AND gate 13 outputs a continuous point detection signal = 1 when the output signals of the OR gates 12A to 12H are all “1”. Based on this continuous point detection signal = 1, the disc reproduction data D (and the disc reproduction data) are output. The data interpolation flag C2D) is stored in the DRAM 5 so as to be continuous with the memory data M.
[0017]
【The invention's effect】
As described above, according to the present invention, the data stored in the memory is interpolated when comparing the data read from the disk with the data stored in the memory when returning after the servo is released. If it is determined that the data coincide with each other, the probability of detecting continuous points of data can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of a disc data continuous point detecting apparatus according to the present invention.
FIG. 2 is an explanatory diagram showing comparison target data by the data comparison block of FIG. 1;
FIG. 3 is a block diagram showing in detail the data comparison block of FIGS. 1 and 2;
FIG. 4 is an explanatory diagram showing CD and MD EFM frames;
FIG. 5 is an explanatory diagram showing a format of CD and MD.
FIG. 6 is an explanatory diagram showing a state in which the servo is disconnected.
[Explanation of symbols]
1 CD (disc)
4 CD signal processing IC (disc signal processing circuit)
5 DRAM (memory means)
7 Data comparison block (data comparison means)

Claims (1)

A disk signal processing circuit that outputs an interpolation flag indicating whether or not the interpolation has been performed, and interpolates and outputs the data read from the disk when the error cannot be corrected by error correction;
Storage means for storing data output from the disk signal processing circuit and an interpolation flag;
When comparing the plurality of word data output from the disk signal processing circuit and the plurality of word data stored in the storage means when returning after the servo is released, the data side stored in the storage means When the interpolation flag added to each word is considered to be a match, it outputs a continuous point detection signal, and when the interpolation flag is off, a continuous point detection signal is output when the comparison results match. Data comparison means to
A device for detecting continuous points of disc data.

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