JPH02130764A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To decode digital data with simple constitution by reading a regenerative output from a recording medium with a differential detecting means marking 4 channel bits which are higher than others in regenerative output of every 11 channel bits and performing a code conversion processing on this detected output in corresponding to an encoder. CONSTITUTION:The number of channel bits per byte in digital data recorded on an optical disk 1 is set as 11 channel bits by the encoder 22 provided in a recording system 20. Among bit patterns of combination of 11C4 setting the number of marks in these bits as 4 channel bits, the conversion is made into code data except a continuous mark pattern of 4 bits and such a bit pattern as 3 or 2 bits or 2 or 3 bits of mark are located before and after a 1-bit space. Then, the differential detecting operation marking 4 bits which are higher signal level among every 11-bit unit with a preamplifier 31 in the reproducing system 30 is performed, so that the detected output is converted by the decoder 34 into a code corresponding to the encoder 22.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an optical recording and reproducing apparatus that records and reproduces digital data using an optical or magneto-optical signal recording and reproducing method.

80 Summary of the Invention The present invention provides an optical recording and reproducing apparatus for recording and reproducing digital data using an optical or magneto-optical signal recording and reproducing method, in which the number of channel bits for each byte of the digital data is reduced to 11 channels. bit, 1
Among the bit patterns of 11C4 combinations in which the number of marks in one channel bit is 4 channel bits, there are bit patterns in which the mark is 4 channel bits consecutively, and 3 channel bits or 2 channel bits before and after the space of 1 channel bit. 11 Regarding the reproduction output from the optical recording medium by converting the digital data into IIR and recording it on an optical recording medium into the code data of the bit pattern excluding the bit pattern in which the mark and the mark of the 2-channel bit or the 3-channel bit exist. The four channel bits with the highest playback output level are read as marks for each channel bit, and the code conversion process corresponding to the code conversion process in the recording system is performed on the read detection output, thereby simplifying the recording and playback of digital data. This has been made so that it can be done reliably.

C9 Prior Art Conventionally, in an optical recording and reproducing apparatus that records and reproduces digital data using an optical recording medium such as a write-once optical disk or a rewritable magneto-optical disk, for example, recording tracks of an optical disk are recorded at predetermined intervals. A so-called sampling servo control has been proposed in which a servo signal is recorded every rotation angle or every predetermined rotation angle, and the discrete servo signals are sampled when the disk is rotated to perform continuous servo control.

Furthermore, as disclosed in US Pat. No. 4,646,281, for example, as a modulation and encoding method for digital data recorded and reproduced via an optical recording medium, the number of channels per byte is 15, and 15 channels are used. A so-called 4/15 code modulation and coding method is adopted in which 4 channel bits are marked (logical "l"), and the playback output from the optical recording medium is sampled using the standard channel clock, resulting in 15 channels. A data reading method using so-called differential detection has been proposed, in which the upper four channel bits having the highest level among the bits are detected in units of 15 channel bits.

D0 Problems to be Solved by the Invention Incidentally, in an optical recording and reproducing apparatus that records and reproduces digital data optically or magneto-optically via an optical recording medium, there is a problem that corresponds to the digital data recorded on the optical recording medium. If the interval between data bits is narrow (there is a problem that it is likely to be affected by so-called code amount interference. 4/1 above)
Adopting a 5-code modulation coding method in the recording system and using the differential detection described above for reading data in the reproduction system is effective in reducing the occurrence of errors due to the influence of the so-called code amount interference described above. However, it is necessary to process data from the recording system encoder to the reproduction system decoder at a channel clock frequency that makes the number of channels per byte 15. Also, 4/15 where 4 channel bits out of 15 channel bits are marked (logical "l")
In the code modulation coding method, the bit pattern with the maximum code amount interference includes a bit pattern in which there is a minimum space of two channel bits (logic "0") between marks (logic "1"), and this When performing differential detection by sampling the playback output for a bit pattern using the channel clock, errors may occur because the space (logic "0") is sampled at a position that deviates from the minimum level, as shown in Figure 4. There is a risk of detection.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, the present invention aims to facilitate data processing by lowering the channel clock frequency when optically or magneto-optically recording and reproducing digital data via an optical recording medium. It is an object of the present invention to provide an optical recording/reproducing apparatus having a novel configuration that reduces the risk of detection errors in the bit pattern with the maximum amount of code interference.

Means for Solving the First Problem In order to solve the above-mentioned problems, the optical recording and reproducing apparatus according to the present invention has a recording system for recording digital data on an optical recording medium, in which each byte of the digital data is recorded. 1, where the number of channel bits in is 11 channel bits, and the number of marks in 11 channel bits is 4 channel bits.
Among the bit patterns of Icd combinations, there are bit patterns in which marks are continuous for 4 channel bits, marks for 3 channel bits or 2 channel bits, and marks for 2 channel bits or 3 channel bits before and after a space for 1 channel bit. An encoder is provided for converting the digital data into code data with a bit pattern excluding the bit pattern, and a reproduction system for reproducing the digital data recorded on the optical recording medium has 11 channels for reproduction output from the optical recording medium. The present invention is characterized by being provided with differential detection means for reading the four channel bits with higher playback output levels as marks for each bit, and a decoder that performs code conversion processing corresponding to the encoder on the detection output by the differential detection means. It is said that

11 Effects In the optical recording/reproducing apparatus according to the present invention, the encoder provided in the recording system is configured to encode 1Ic4 in which the number of channel bits per byte of digital data is 11 channel bits, and the number of marks in the 11 channel bits is 4 channel bits. Among the combinations of bit patterns, the mark is a bit pattern in which 4 channel bits are consecutive, and 1
Convert the above digital data to 4/11 modulation code data of a bit pattern excluding bit patterns in which a mark of 3 channel bits or 2 channel bits and a mark of 2 channel bits or 3 channel bits exist before and after the channel bit space. . and,
The recording system records digital data converted into 4/11 modulation code data by the encoder onto an optical recording medium.

Furthermore, in the reproduction system of the optical recording and reproduction apparatus according to the present invention, the differential detection means reads the four channel bits with the higher reproduction output level as marks in units of 11 channel bits with respect to the reproduction output from the optical recording medium. Digital data is reproduced by performing decoding processing of 4/11 modulation code data on this read detection output in a decoder.

G. Embodiment Hereinafter, an embodiment of the optical recording/reproducing apparatus according to the present invention will be described in detail with reference to the drawings.

The embodiment shown in the block diagram of FIG.
The optical disk (10) is rotated by the spindle motor (2) at a constant angular velocity while
1) The present invention is applied to a write-once type optical recording and reproducing apparatus that optically records and reproduces digital data by scanning an upper recording track with a laser beam.

The above-mentioned optical disk (1) has a recording format as shown in FIG.
It is divided into sectors (SCl) to (SCii).

Each of the above sectors (SC+) to C5C*t> divides one sector into 76 segments (SG, ) to (SCya,), and also divides one segment into a 2-byte control recording area (
AR, ) and an 8-byte data recording area (ARn), and furthermore, the control recording area (ARc) is divided into a preformat area (API
), trunking information bits (Pw+, Pz), and clock information pits (pct) into a preformat area (ARt) and a focus information area (ARC).

In the optical recording/reproducing apparatus of this embodiment, the data recording area (
Recording system (20) for recording digital data on 8Re)
is an encoder (22) into which digital data DIM to be recorded is input via an input/output interface (21).
), a write pulse generation circuit (23) that performs a pulse operation according to the encoded output from the encoder (22).
), a laser drive circuit (24) that pulse-drives a laser diode of the optical head (10) in response to a write pulse given by the write pulse generation circuit (23).
), encoder (22) and write pulse generation circuit (2
3) is composed of a timing generation circuit (25) that provides an operation timing clock.

The encoder (22) converts the number of channels per byte (8 bits) into 11 for the digital data DIN input via the input/output interface (21).
channel, and the number of marks (logical "l") in 11 channel bits is 4 channel bits. Among the bit patterns of the combination of 1C4, the bit pattern (1111) in which the mark is continuous for 4 channel bits, and!
3 before and after the channel bit space (logical “O”)
Bit patterns (111011), (110
Encoding processing is performed to form 4/11 modulation code data of a bit pattern excluding (111) and (1110111).

Here, the encoder (22) converts the digital data D1 into four channels, such as those shown in A-H of Table 1, in which the logical "0" channel bits, that is, spaces are not consecutive for more than lθ channel bits. It is composed of a conversion table memory in which /11 modulation code data is written in advance.

B in Table 1: 4/1 1 modulation code data A in Table 1: 4/1 1 modulation code data C in Table 1: 4/1 1 modulation code data D in Table 1: 4/1 1 modulation F in code data table 1: E in 4/11 modulation code data table 1
: 4/1 ■ Modulation code data G in Table 1: 4/1 1 Modulation code data H in Table 1: 4/11 Modulation code data And the above recording system (20) in the optical recording/reproducing apparatus of this embodiment Then, the digital data DIN to be recorded is converted by the encoder (22) into the 4/11 modulation code data shown in Table 1 A to H, and a pulse generation operation is performed according to the encoded output of this encoder (22). The laser drive circuit (24) pulse-drives the laser diode of the optical head (10) in response to the write pulse generated by the write pulse generation circuit (23), thereby generating the digital data D9. 4 is the above 4/1
1 modulation code data is recorded in the data recording area (ARo) on the recording track (TR) of the optical disc (1).

The timing generation circuit (25) generates a channel clock for 4/11 modulation code data in synchronization with the pit clock of the digital data DIN to be recorded, and uses this channel clock as an operation timing clock for the encoder (25). 22) and the write pulse generation circuit (23).

Here, the number of channels per byte (8 bits) is 11.
channel, and the number of marks (logical "1") in 11 channel bits is 4 channel bits. Among the bit patterns of combinations of II C4, the bit pattern in which marks are continuous for 4 channel bits and the space of 1 channel bit ( The bit patterns shown in A-H in Table 1 above are the bit patterns excluding the bit patterns in which there is a 3-channel bit or 2-channel bit mark and a 2-channel bit or 3-channel bit mark before and after the logic "O"). In addition to the above 256 types, there are bit patterns such as those shown in Table 2, and these bit patterns may be arbitrarily made to correspond to 1-byte data of the digital data DIN to be recorded.

[Margin below]

Table 2 also shows that in the optical recording/reproducing apparatus of this embodiment, code data recorded by the recording system (20) in the data recording area (ARM) on the recording rack (TR) of the optical disk (1) In the reproduction system (30) for reproducing digital data, the optical head (lO) detecting the return light from the recording track (TI+) is connected to the optical disc (10).
1) scanning the recording track (TR) with a laser beam and detecting the return light from the recording track (TR);
The detection output is supplied to a timing generation circuit (32) and an A/D conversion circuit (33) via a preamplifier (31), and the output of the A/D conversion circuit (33) is supplied to a decoder (
34).

The timing generation circuit (32) is configured to operate on the optical disc (
1) A channel clock is formed based on the detection output of the clock information bit (PCll) of the control recording area (ARc) which is provided discretely in advance on the recording track (TR) as described above. The above A/D conversion circuit (3) uses the channel clock as the operation timing clock.
3) and the decoder (34).

Further, the A/D conversion circuit (33) samples the detection output from the optical head (10) supplied via the preamplifier (31) using the channel clock as an operation timing clock. , A/D conversion processing is performed by a differential detection operation in which four channel bits with the highest signal level are marked (logic "1") in units of 11 channel bits.

The decoder (34) then sends the encoder (22) of the recording system (20) to the 4/11 modulation code data read by the A/DI loss circuit (33) through a differential detection operation in units of 11 channel bits. ), the digital data Dou! Play.

In the optical recording/reproducing apparatus of this embodiment, the recording system (20)
The digital data DIM is recorded in the recording track (TI?) of the optical disc (1) as 4/11 code data with 1 byte of 11 channel bits and the number of marks in the 11 channel bits fixed at 4 channel bits, so the above playback 11 Regarding the detection output by the optical herad (10) in the A/D conversion circuit (33) of the system (30)
4 from the highest signal level in channel bit units
A/D conversion processing can be performed using a differential detection operation using a channel bit as a mark (logic "1").

In addition, the 4/11 modulation code data has a longer channel focus period than the conventionally known 4/15 modulation code data, so it has a larger time margin, and the encoder of the recording system (20) (22) and regeneration systems (
30), the A/D conversion circuit (33), decoder (34), etc. can have a simple configuration with slow operation speed. Moreover, in the 4/l 1 modulation code data, in the A/D conversion circuit (33) of the reproduction system (30), a space of one channel bit (
When differential detection is performed by sampling the playback output for the bit pattern with the maximum code amount interference (logic "0") using the channel clock, as shown in FIG.
Since the space (logic "O") is sampled at the minimum level position, the risk of false detection is extremely low, and highly accurate A/D conversion processing can be performed.

H0 Effects of the Invention In the optical recording and reproducing apparatus according to the present invention, the number of channel bits for each byte of digital data is 11 channel bits, and the number of marks in the 11 channel bits is 4 channel bits. Among these, the focus pattern excludes bit patterns in which marks are continuous for 4 channel bits, and bit patterns in which marks for 3 channel pits or 2 channel bits and marks for 2 channel bits or 3 channel bits exist before and after a space for 1 channel bit. The above digital data is converted into 4/11 modulation code data and recorded on an optical recording medium, and the playback output from the optical recording medium is converted into 4/11 modulation code data, whichever has a higher playback output level, by a differential detection means in units of 11 channel bits. Digital data is reproduced by reading the channel bit as a mark and decoding the 4/11 modulation code data using a decoder based on the read detection output.

In this way, by performing recording and reproducing with the number of channels for each byte of digital data set to 11, the channel clock frequency can be lowered to facilitate data processing and the configuration can be simplified. Also, the marks among the 11 channel bits are assumed to be 4 channel bits. Among the bit patterns of 1C4 combinations, a bit pattern in which the marks are consecutive 4 channel bits,
Recording and reproducing digital data as 4/11 modulation code data of bit patterns excluding bit patterns in which marks of 3 channel bits or 2 channel bits and marks of 2 channel bits or 3 channel bits exist before and after a 1 channel bit space. Therefore, when differential detection is performed by sampling the playback output for the bit pattern with the maximum code amount interference, where there is one channel bit of space between marks, using the channel clock, the data in the space is detected at the minimum level position. is sampled, and the probability of detection error can be reduced.

Therefore, in the optical recording and reproducing apparatus according to the present invention, recording and reproducing of digital data can be reliably performed with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an optical recording/reproducing apparatus according to the present invention, FIG. 2 is a schematic diagram showing a recording format of an optical disc used in the optical recording/reproducing apparatus, and FIG.
The figure shows 4/4 reproduced from the recording track of the optical disc.
1 This is a raw waveform diagram. FIG. 4 is a reproduction waveform diagram of a 4/1 modulation code reproduced from the recording trunk of the conventionally known optical disk. (1)......Optical disk (10)...Optical head (20)...Recording system (22)...Encoder (23)...Write pulse generation circuit (2
4)... Laser drive circuit (30)...
...Reproduction system (32) ...Timing generation circuit (33)
......A/D conversion circuit (34)...
··decoder

Claims (1)

[Claims] In a recording system for recording digital data on an optical recording medium, the number of channel bits for each byte of the digital data is 11 channel bits, and the number of marks among the 11 channel bits is 4 channel bits._1_1C_
Among the bit patterns of 4 combinations, the mark is 4
The above applies to the code data of bit patterns excluding bit patterns with continuous channel bits and bit patterns with marks of 3 channel bits or 2 channel bits and marks of 2 channel bits or 3 channel bits before and after a space of 1 channel bit. An encoder for converting digital data is provided, and a reproduction system for reproducing the digital data recorded on the optical recording medium is provided with an encoder that converts the reproduction output from the optical recording medium.
A differential detection means for reading the four channel bits having a higher playback output level as a mark for each channel bit, and a decoder for performing code conversion processing corresponding to the encoder on the detection output by the differential detection means. An optical recording/reproducing device characterized by: