Dynamic information storage or retrieval – Binary pulse train information signal – Binary signal gain processing
Patent
1995-05-25
1996-10-15
Epps, Georgia Y.
Dynamic information storage or retrieval
Binary pulse train information signal
Binary signal gain processing
395 238, H04N 576, G10L 302
Patent
active
055661548
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates to a recording/reproduction of compressed data in which digital audio signals, etc. are caused to undergo bit compression, a recording medium adapted so that those compressed data are recorded therein, and a transmission system for compressed data, and more particularly to a digital signal processing apparatus, a digital signal processing method and a data recording medium, which are suitable when used in the case of carrying out, in dependency upon amplitude change of a waveform on the time base of an input signal, information compression of such a digital signal to vary size in point of time (length) of a block subject to processing thereof to conduct recording or transmission and/or reproduction or reception of such a compressed digital signal to expand it.
2. Background Art
The applicant of this application has already proposed, e.g., in the Japanese Patent Application Laid Open No. 105269/1992, the Japanese Patent Application Laid Open No. 105270/1992, the Japanese Patent Application Laid Open No. 105271/1992, and the Japanese Patent Application Laid Open No. 6572/1993 of the Japanese Laid Open Patent Publications, etc., such a technology to implement bit compression to an inputted digital audio signal to record them in a burst manner with a predetermined data quantity being as a recording unit.
This technology is a technology using a magneto-optical disc as a recording medium and adapted for recording/reproducing AD (Adaptive Difference) PCM audio data standardized by the audio data format of so called CD-I (CD-Interactive), CD-ROM XA, wherein such audio data are recorded onto the magneto-optical disc in a burst manner with, e.g., 32 sectors of the ADPCM data and several linking sectors for interleaving processing being as a recording unit.
In the case of such ADPCM audio data in a recording/reproducing apparatus using a magneto-optical disc, several modes can be selected. For example, there are prescribed (provided), e.g., level A where compression rate is 2 when viewed from comparison with reproduction time of the ordinary CD and sampling frequency is 37.8 kHz, level B where compression rate is 4 when similarly viewed and sampling frequency is 37.8 kHz, and level C where compression rate is 8 when similarly viewed and sampling frequency is 18.9 kHz. Namely, for example, in the case of the level B, digital audio data is compressed into substantially one fourth (1/4), and reproduction time (play time) of the disc recorded in the mode of the level B becomes equal to a value four times greater than that in the case of the standard CD format (CD-DA format). This permits the apparatus to become compact because recording/reproducing time which is the same order as that of the more compact standard 12 cm disc can be obtained.
In this instance, since rotation speed of the disc is the same as that of the standard CD, compressed data corresponding to reproduction time four times greater than that of the standard CD per a predetermined time will be obtained, e.g., in the case of the level B. For this reason, an approach is employed to read out four times, in a overlapping manner, the same compressed data in time units, e.g., sector or cluster, etc. to use, for reproduction of audio data, only data of one read-out operation thereof. In actual terms, in scanning (tracking) recording tracks in a spiral form, such a track jump to return to the original track position every one rotation is carried out to successively conduct reproducing operation in such a form to carry out tracking of the same track repeatedly by four times. This means that it is sufficient that normal (correct) compressed data can be obtained by at least only one read operation of, e.g., four times of overlapping (repetitive) read operations. Employment of such an approach is tolerant of error by disturbance, etc. and is preferable particularly when applied to portable compact (small-sized) equipments.
Further, the applicant of this application has proposed, in the Japanese Patent Application
REFERENCES:
patent: 5293252 (1994-03-01), Kim et al.
patent: 5471558 (1995-11-01), Tsutsui
Epps Georgia Y.
Huber P. W.
Sony Corporation
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