JPH0411944B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides information storage on an optical disk in which a track has a sector structure divided into a plurality of areas, and each sector has a frame structure consisting of a plurality of information recording units. The present invention relates to an optical information recording and reproducing method for recording and reproducing information.

Conventional structure and its problems As an optical information recording/reproducing device, for example, an optical recording disk coated with or vapor-deposited with a photosensitive material is rotated, and a beam from a laser light source is directed onto the disk surface with a diameter of 1 μm or less. By irradiating a finely focused spot of light and modulating its optical output intensity with a recording signal, optical changes such as phase changes due to irregularities or changes in reflectance and transmittance can be detected on the optical recording disk in real time. There are devices that can record information such as video signals and digital signals, and can reproduce the recorded information by detecting changes in the optical characteristics.

In such devices, optically detectable guide tracks are provided in advance in concentric circles or spirals on the tracks to be recorded, in order to increase the density of recording tracks, discrete partial writing, erasing, etc. An optical information recording apparatus is conceivable that performs known tracking control so that the minute spot light follows the guide track, records information on a predetermined track, and reproduces information from the track.

When recording digital information whose data length is variable, in order to use the recording area efficiently, the track is divided into multiple areas (sectors).
Some devices record and reproduce information on a sector-by-sector basis. A conventional data recording format is shown in FIG. Each sector consists of a synchronization signal 1 for synchronizing the self-regenerating clock generation circuit, a data mark 2 for identifying the beginning of data, and a data section 3.

As shown in FIG. 2, block B in which synchronization signal 1, data mark 2, and data section 3 are connected is inserted and recorded in the period from sector mark S to the next sector mark S for identifying sectors. be done. Between the sector mark S and the recording signal block B, the sector mark and the recording signal should not overlap even if there is a time axis fluctuation due to phase fluctuation of the disk motor, vibration of the recording/reproducing head, eccentricity of the disk, etc.; Since a preparation period is required for signal recording and reproduction, margin times T ₀ and T ₁ must be provided, respectively.

Data mark 2 is composed of a special bit string that does not appear in data, and bit synchronization for data reproduction in a sector is performed once per sector.

Currently, block code methods such as 2/3 conversion are being used as high-density modulation methods.
In this method, if there is a dropout of the signal due to dropouts or scratches on the recording medium, the word synchronization between the data during modulation and the data during demodulation may deviate. Once word synchronization is lost, correct demodulation cannot be performed because the word synchronization is continued until the next data mark is detected.

To reduce errors caused by word synchronization,
In general, it is possible to reduce the capacity of one sector and increase the number of sectors, but since margin times T ₀ and T ₁ shown in Figure 2 are required between sectors, increasing the number of sectors will increase the overall recording capacity. will decrease.

For this reason, a frame structure may be considered in which one sector is further divided into a plurality of information recording units (frames). FIG. 3 shows an example of a frame structure recording format. Each frame F consists of a synchronization signal 1 for synchronizing the clock regeneration circuit, a data mark 2 for identifying the beginning of data, a frame number section consisting of a frame serial number and an error detection code, and a data section 3. , a plurality of frames F constitute one sector recording signal block B.

In data reproduction, the frame number is identified after the data mark is detected, and if there is no error in the frame number, the data is stored in the buffer memory address corresponding to the frame number, and the data reproduction sequence is completed for each sector.

Here, as a method of outputting a signal indicating the end of the data reproduction sequence, there is a method of counting the number of detected data marks and outputting a reproduction end signal when the number of detected data marks becomes equal to the number of frames of one sector, or, One possible method is to output a playback end signal when the last frame is identified.
In the former case, when one part of the data mark cannot be detected, and in the latter case, when the last frame cannot be identified, the reproduction end signal is not output at the respective predetermined positions, and the reproduction sequence of one sector is stopped. If it does not end, it will affect the next sector playback.

OBJECTS OF THE INVENTION An object of the present invention is to provide an optical information recording and reproducing method that reliably outputs a reproduction sequence end signal for each sector when reproducing data from a sector recording signal having a frame structure on an optical recording disk.

Composition of the Invention The present invention identifies a frame and identifies the frame in data reproduction of a sector consisting of a synchronization signal, a data mark, a frame number part consisting of a frame serial number and an error detection code, and a series of frames consisting of data. If there is no error, load a value corresponding to the frame number into a counter that uses the readout clock as a clock input, and generate a data reproduction sequence end signal that is performed for each sector when the counter output reaches a preset value. So, even if there is no data mark detected or frame number erroneously detected in the sector,
It always outputs a data reproduction sea case end signal.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 4 shows one of the optical recording disks used in the present invention.
This is an example. The optical recording disk 5 is _S1
A sector area 6 for information recording consisting of ~S _N ,
It is composed of sector marks 7 that record sector address information consisting of S _n1 to S _nN . Information is recorded and reproduced in sector units.

The data actually recorded on the optical recording disk is processed according to a certain conversion algorithm in order to easily extract clock pulses for self-clock reproduction and to create a signal form suitable for the recording medium. This is data that has been modulated.

When trying to play back data in a sector,
In order to extract and demodulate only the data portion of the recorded signal, a data mark is detected from the binary signal after waveform equalization, and demodulation of the data is started at that timing.

In the recording format used in the present invention, as shown in FIG. 3, a sector is composed of a plurality of frames F, and each frame has a frame number section consisting of a synchronization signal 1, a data mark 2, a frame serial number, and an error detection code. 4. It consists of a data section 3.

FIG. 5 shows a block diagram of data reproduction. The reproduced signal 9 taken out from the photodetector 8 is transmitted to the amplifier 1
0, passes through the waveform equalizer 11 and comparator 12 2
This becomes a digitized reproduction signal 13. Binarized playback signal 13
In accordance with the clock pulse 15 extracted by the clock recovery circuit 14, the shift register 16 is
The data mark detection circuit 17
When a particular bit pattern is detected, a data mark detection signal 18 is output. This data mark detection signal 18 generates a reproduction gate signal 19 and a reproduction timing clock signal 20.
However, the regeneration gate and timing clock generation circuit 2
1, and using these signals, a frame number detection/check circuit 22 first detects a frame number signal 23 indicating the number of frames, and a frame number signal 23 indicating whether or not there is an error in the bit string indicating the frame number using an error detection code. A number check signal 24 is output, and an address conversion circuit 25 specifies an address 27 of the sector buffer memory 26 corresponding to the frame number. The demodulated data 28 of the current frame is written into the memory section indicated by this address, and this cycle is repeated for the number of frames of one sector, completing the loading of one sector of reproduced data.

When data is reproduced in units of sectors, the number of detected data marks is counted and output as a means for obtaining a sector reproduction end signal indicating where reproduction data acquisition has been completed. Output after the last frame is played. There are methods such as the following, but if any data mark is not detected, if the data mark of the last frame is not detected, or if a frame number error is detected, the reproduction end signal cannot be output.

FIG. 6 is a block diagram showing a reproduction end signal output circuit according to the present invention.

The output 29 of the ROM 28 corresponding to the frame number signal 23 is loaded into the counter 30 by the frame number check signal 24 which is output when there is no error in the bit string representing the frame number. The counter is output for each sector and counts the reproduction clock pulses 15 only while the reproduction enable signal 31 indicating that reproduction is in progress is "ON". It is set to a value that is output after the import is completed, and this carry is used as the reproduction end signal 32. This reproduction end signal turns the reproduction enable signal 31 into the "OFF" state, thereby completing the reproduction sequence of one sector.

As an example, FIG. 7 shows a time chart when one sector is composed of three frames.

When the playback enable signal becomes “L”,
The data mark signal of frame 1 is detected,
When the frame number is imported and the frame number check signal is output, this
The FNAS loads the counter with a value that outputs a carry if it counts 150 regenerated clock pulses. Similarly, in frame 2, 100
, and in frame 3, set a value such that a carry is output after counting 50 regenerated clock pulses.
Load into counter. The carry signal of this counter is used as a reproduction end signal, and the reproduction enable signal is set to "H" to complete reproduction of one sector.

If you generate a playback end signal in this way,
Even if no data mark is detected in an intermediate frame, the reproduction end signal is always output at the end of one sector based on the frame number of the last detected frame and the frame number check signal.

Effects of the Invention As is clear from the above description, the present invention provides an optical recording disk having a sector made up of a plurality of frames. By providing a circuit that outputs a playback end signal, the playback sequence is always ended in units of one sector, thereby preventing error propagation to the next sector, data playback stop, etc. that occur when the one sector playback end signal is not output. can be done, and its practical effects are great.

[Brief explanation of drawings]

FIG. 1 is a format diagram showing an example of a conventional recording format, FIG. 2 is a layout diagram showing the positions of sector marks and recording blocks, FIG. 3 is a format diagram showing a frame structure data recording format, and FIG. 4 is a format diagram showing an example of a conventional recording format. The figure is a pattern diagram showing one example of an optical recording disk, FIG. 5 is a block diagram of data reproduction, FIG. 6 is a circuit diagram showing a reproduction end signal output circuit, and FIG.
The figure is a time chart when reproducing one sector.

Claims (1)

[Scope of Claims] 1. An optical disk having an optically detectable guide track, wherein the guide track is divided into a plurality of sectors, and data to be recorded in the sector is divided into a plurality of segments, A serial number with an error detection code is added to each segment, a data mark is added at the beginning of each segment to which the serial number is added with an error detection code, and a data mark is added to the beginning of the segment, and the data is played immediately before the data mark. As a frame structure with a synchronization signal for clock pull-in, when an information recording unit consisting of multiple frames is recorded in a sector, the reproducing circuit has a counter that counts the read clock, and when reproducing the sector, the clock is A value corresponding to the number of read clocks until the end of sector reproduction, which is uniquely converted from the detected serial number, is loaded into the counter only when there is no error in the serial number, and the counter output becomes a preset value. An optical information recording and reproducing method characterized in that, at times, this counter output is used as a sector reproduction end signal. 2. Optical information according to claim 1, characterized in that a serial number check signal that is generated when there is no error in the bit string indicating the serial number due to an error detection code added to the serial number is used as a load signal to the counter. Recording and playback method.