Dynamic magnetic information storage or retrieval – General processing of a digital signal – Data in specific format
Reexamination Certificate
1998-09-15
2001-01-09
Faber, Alan T. (Department: 2753)
Dynamic magnetic information storage or retrieval
General processing of a digital signal
Data in specific format
C360S053000, C360S069000, C360S060000
Reexamination Certificate
active
06172829
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
This invention relates to a data recording method and apparatus for recording digital audio data or computer data on, a tape-shaped recording medium and to a data reproducing method and apparatus for reproducing digital audio data or computer data from a tape-shaped recording medium.
2. Description of the Related Art
There has so far been known a digital audio tape recorder (DAT) for recording digital audio signals on a recording track inclined relative to the running direction of a magnetic tape by a rotary head for the purpose of reducing the length of the magnetic tape required for recording.
Since the DAT can reduce consumption of the magnetic tape and elevate the data rate during recording, it is preferentially used in a tape recorder, known as a data streamer, used for protecting computer data written on a hard disc.
When using the DAT as a tape recorder, data from the host computer is converted into a DAT format data prior to recording.
In the DAT format, a frame is completed by two inclined tracks formed during one complete revolution of two heads having different azimuth angles, and 16-bit PCM audio signals are interleaved and recorded on the frame basis. Each track is made up of 196 blocks, each block being formed by 36 bytes. This track is roughly divided into seven areas, as shown in FIG.
1
.
Both end marginal areas M are spare areas for realizing stable contact between the tape and the head. Two sub-data areas are those used for recording subcodes which are a variety of signals, such as time or addresses. Two automatic track finding (ATF) areas are those areas for recording the ATF signals and for achieving automatic track finding via the recording head. A main area D is an area for recording main audio data. In this main area D are recorded the main audio data, error correcting parity and part of the subcodes ancillary to the audio data. The main area D is made up of 128 blocks, each being formed by 36 bytes.
Each of 128 blocks of the main area D has synchronization signals, PCM-IDs, block addresses and a parity, each of one byte, beginning from the leading end of the block. In the next following 32-byte area is arranged main data.
If the data is audio signals, the main data is 16-bit PCM data of the left channel (L) and the right channel (R). This 16-bit main data is interleaved and arranged in the main area of two tracks, that is one frame, along with the parity Q. In this case, approximately 5760 bytes of data are recorded in the main area of one frame.
Since each track is divided in the DAT format into a main area and a sub-area, after-recording can be made using the sub-area.
The structure of the error correction code of main data in the DAT format is the two-dimensional code, as shown in
FIG. 3
, with the code planes being, four planes per track, each being coded in C
1
and C
2
directions.
If the DAT is used as a data recorder, data sent from the host computer is 16-bit data handled in the same manner as the above-mentioned PCM data. These data are formatted and recorded in the one-frame main area. In this case, data of the two bytes and 16 bits corresponding to L and R channels are used, and upper four bits thereof are used as format ID, while the lower eight bits are recorded as logical frame numbers. The format ID specifies a format proper to the data recorder. The logical frame number has 23 frames, for example, as a unit, and frame numbers of 1 to 23 are attached on the unit basis.
With the data recorder, employing such DAT, a higher transfer rate and a larger capacity have recently been realized in keeping up with the progress in the format. The data recorder format is prescribed by, for example, the standard of the European Computer manufacturers Association (ECMA). Recently, the recording density is improved by narrowing the track pitch or changing the recording format, such that a data recorder of the third generation has now been prescribed.
The data recorders of the first, second and third generations are termed a DDS (digital data streamer), DDS
2
and DDS
3
, respectively.
Meanwhile, audio data for DAT cannot be recorded at present in a tape cassette for DDS
2
nor in a tape cassette for DDS
3
.
The above-mentioned DDS
2
and DDS
3
have been utilized as a data recorder for computers, and are not inherently required to have the function of recording or reproducing audio data for DAT. However, if the user in possession of the DDS
2
or DDS
3
desires to record or reproduce audio data for DAT, it is inconvenient if he or she is compelled to purchase a dedicated recording/reproducing apparatus.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a data recording method and apparatus inherently operating as a data recorder and which nevertheless can record audio data for DAT.
It is another object of the present invention to provide a data reproducing method and apparatus for reproducing not only computer data but audio data for DAT.
In one aspect, the present invention provides a data recording apparatus including recording system signal processing means for performing recording system signal processing on the audio data- or computer data entered via the interface controller, and control means for controlling the recording system signal processing means responsive to four sorts of data format, namely a format for the audio data, a first computer data format comprised of the audio data format added to with error correction provisions in each track width direction in terms of a defined number of tracks, a second computer data format having a track pitch prescribed to be narrower in track pitch than the first computer data format and a third computer data format having a line recording density higher than in the second computer data format.
The recording system signal processing means preferably includes separation means for separating main and sub-data of the audio data, subcode generating means for generating sub-codes of the computer data, index appendage means for appending the index information to the computer data, C
3
encoding means for appending the C
3
error correction code to a data string in the track width direction in terms of a defined number of tracks of the computer data having the appended index information, interleaving means for interleaving computer data having an appended C
3
error correction code and separated audio main data, C
2
encoding means for appending the C
2
error correction code to a data string in the track direction of the deinterleaved computer data or audio main data, subcode appendage means for appending the separated audio sub-code to the audio main data and for appending the sub-code of the computer data to the computer data, C
1
encoding means for appending the C
1
error correction code to each defined block unit of audio main data having appended audio sub-codes and computer data having appended computer data subcodes, block-forming means for blocking the audio data or computer data having appended C
1
error correction code and for appending the subcodes for the computer data from the subcode appendage means to the computer main data from the C
1
encoding means and for blocking the resulting data, modulating means for modulating the blocked audio data or computer data and synchronization signal appendage means for appending the synchronization signals to a modulated output of the modulation means.
The subcode generating means preferably executes first subcode generating processing or second subcode generating processing if the input computer data is the first or second computer data format or if the input computer data is the third computer data format, respectively.
The C
3
encoding means preferably executes first C
3
encoding or second C
3
encoding if the input computer data is of the first or second computer data format or if the the input computer data is of the third computer data format, respectively.
The interleaving means preferably executes first interleaving or second interleaving if the input dat
Iijima Tatsuya
Ozaki Shinya
Yamada Masaki
Faber Alan T.
Maioli Jay H.
Sony Corporation
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