Dynamic information storage or retrieval – Binary pulse train information signal – Changing a system mode
Reexamination Certificate
1993-09-29
2001-03-20
Young, W. R. (Department: 2615)
Dynamic information storage or retrieval
Binary pulse train information signal
Changing a system mode
C369S084000
Reexamination Certificate
active
06205104
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a recording and/or reproducing apparatus for compressed data obtained on bit compression of digital audio signals. More particularly, it relates to a recording and/or reproducing apparatus in which at least a signal reproducing system and a signal recording system are provided separately from each other.
In e.g. JP Patent Applications Nos. 2-221364, 2-221365, 2 -222821 and 2-222823, the present Assignee has proposed a technique of bit compressing input digital audio signals and recording them in a burst fashion based on a predetermined volume of data as a recording unit.
With this technique, AD (adaptive differential) PCM audio data prescribed in an audio data format of CD-ROM XA or CD-I (CD-Interactive) are recorded on or reproduced from a magneto-optical disc used as a recording medium in a burst fashion. Recording is made in this case with e.g. 32 sectors of the ADPCM data and several linking sectors as a recording unit for interleaving. Table 1 shows ADPCM audio levels in CD-I format or CD-ROM XA format in conjunction with standard CD (compact disc) format (CD-DA format).
TABLE 1
sampling
number of bits
dynamic
CD-
frequency
for quantization
range
bandwidth
playback time
ROM
level
(kHz)
(bit)
(db)
(kHz)
stereo
monaural
CD-I
XA
PCM
CDDA
44.1
16
98
20
1
—
∘
∘
AD
A
37.8
8
90
17
2
4
∘
—
PCM
B
37.8
4
90
17
4
8
∘
∘
C
19.8
4
90
8.5
8
16
∘
∘
Referring to Table 1, in e.g. the level 8 mode, digital audio data are compressed to approximately ¼, such that the playback time of a disc recorded with the level B mode is four times that with a standard CD-DA format. This means that, since the recording/playback time about equal to that of a standard disc with a diameter of 12 cm may be achieved with a smaller size disc, the size of the recording and/or reproducing apparatus may be correspondingly reduced.
However, with the level B mode, for example, the four channel ADPCM data are presented cyclically at an interval of four sectors as the inherent recording data conforming to the CD-I format, so that, when a single channel is reproduced, it becomes necessary to take out one sector data out of four sector data periodically. However, it is practically impossible to effect recording of a channel of ADPCM data because of the problem of interleaving extending to adjoining channels. For this reason, with the above mentioned prior-art technology, continuous ADPCM audio data are time compressed at intervals of, for example, 32 sectors, and linking sectors are appended before and after the sector in order to take account of the interleaving extending to data of the adjoining sectors to effect sector-continuous recording in a burst fashion.
Meanwhile, a recording and/or reproducing apparatus, provided with two-channel recording and/or reproducing units, such as a so-called double-cassette tape recorder, has been offered to the market. It is highly probable that the demand will be raised for a recording and/or reproducing apparatus for compressed data which is provided with such two-channel recording and/or reproducing units. If these units were provided separately, production costs would be doubled. On the other hand, it is highly desirable that a so-called dubbing function be accorded to such apparatus provided with the two-channel recording and/or reproducing units so that a predetermined recording medium is reproduced by a reproducing system of one of the units for recording by a recording system of the remaining unit. If such dubbing function is to be implemented by the above mentioned recording and/or reproducing apparatus for compressed data, the same time that is necessary for usual playback is required for dubbing. Thus a function for dubbing at a higher speed is desired.
OBJECT AND SUMMARY OF THE INVENTION
In view of the above described status of the art, it is an object of the present invention to provide a recording and/or reproducing apparatus for compressed data in which at least a reproducing system for compressed data and a recording system for compressed data are provided, and in which signals reproduced from one of the recording media may be recorded in a reduced period of time on the other recording medium.
In accordance with the present invention, there is provided an apparatus for recording and/or reproducing compressed data comprising a reproducing system for compressed data for reproducing bit-compressed digital data from a recording medium, and a recording system for compressed data for recording the bit-compressed digital data in one other recording medium, wherein the compressed data from said reproducing system are transmitted to said recording system for direct recording on said other recording medium.
It is noted that, even when compressed data are read in a burst fashion or intermittently during ordinary reproduction on the basis of a predetermined data volume as a recording unit, the compressed data may be continuously read and transmitted to one other recording medium, that is, without expansion, for recording directly on the other recording medium.
Since the compressed data reproduced from a recording medium are directly recorded on the other recording medium, that is without expansion, so-called high-speed dubbing may be made in conformity to the compression factors.
It will be seen from above that, with the present recording and/or reproducing apparatus, digital data bit-compressed from one of the recording media are reproduced and directly recorded on the other medium, that is without bit expansion, so-called high-speed dubbing conforming to the compression factor may be achieved with high efficiency and in a short time.
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patent: 4775897 (1988-10-01), Umemoto et al.
patent: 4799677 (1989-01-01), Frederiksen
patent: 4811325 (1989-03-01), Sharples, Jr. et al.
patent: 5128910 (1992-07-01), Iida
patent: 56-22231 (1981-03-01), None
patent: 60-202573 (1985-10-01), None
patent: 1-53385 (1989-03-01), None
Ando Ryo
Fujiie Kazuhiko
Maeda Yasuaki
Nagashima Hideki
Obata Hideo
Limbach & Limbach L.L.P.
Oh Seong-Kun
Sony Corporation
Young W. R.
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