Dynamic information storage or retrieval – Information location or remote operator actuated control – Selective addressing of storage medium
Reexamination Certificate
2000-05-19
2002-05-14
Dinh, Tan (Department: 2651)
Dynamic information storage or retrieval
Information location or remote operator actuated control
Selective addressing of storage medium
C369S084000, C369S030050
Reexamination Certificate
active
06388959
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a dubbing apparatus by which information in the form of an audio signal recorded, for example, on a disk-type recording medium can be reproduced and recorded onto another recording medium.
In recent years, disk media onto and from which audio data can be recorded and reproduced such as, for example, a mini disk (MD, trademark) and recording and reproduction apparatus on which such disk media can be used have been popularized widely.
Also an audio system which includes a combination of, for example, a MD recorder/player which is a recording and reproduction apparatus for a MD and a CD player or the like has been popularized widely.
In such a system as a MD recorder/player and a CD player or the like as described above, audio data are managed in a unit called “program”. Here, a program in the present specification signifies a set of data which are managed and recorded in a unit on a disk, and for example, with regard to audio data, it corresponds to one tune (generally called “track”) or the like. Therefore, in the following description, a program may suitably referred to as track.
Such an audio system as described above is usually constructed such that it can effect dubbing recording, that is, recording of audio data reproduced by the CD player onto a MD by the MD recorder/player.
Also a system is available which can effect high speed dubbing to reduce the recording time in such dubbing recording.
Upon high speed dubbing, a disk rotational driving control system and a reproduction signal processing system of the CD player are controlled so that a CD may be played back at a predetermined multiple speed higher than a normal reproduction speed. Also on the MD recorder/player side, a recording signal processing system is controlled so as to operate at a multiple speed corresponding to the reproduction multiple speed for a CD, and receives audio data reproduced by the CD player and records the audio data onto a MD.
For example, in an apparatus wherein a CD player as a reproduction apparatus and a MD recorder/player as a recording apparatus are integrated with each other, it is easy to control the CD player and the MD recorder/player so that they may simultaneously operate at a predetermined multiple speed so as to perform such high speed dubbing as described above. Also in another system wherein a reproduction apparatus and a recording apparatus are formed as separate units from each other, if the system is constructed such that, for example, a controlling cable or the like is used to connect the reproduction apparatus and the recording apparatus to each other so as to allow communication with each other, then high speed dubbing can be realized readily by controlling operations of the reproduction apparatus and the recording apparatus in synchronism with each other.
In a reproduction apparatus for a CD, a disk is driven to rotate in accordance with a CLV (Constant Linear Velocity) method as well known in the prior art, and an EFM signal reproduced from the CD is supplied to a PLL circuit. The PLL circuit is provided in order to produce a channel clock signal synchronized with the EFM signal. When the PLL circuit is in a locked state, the CD is driven to rotate stably at a prescribed CLV speed and a reproduction signal is processed normally.
In such an audio system as described above, when a CD is played back with a multiple speed higher than a normal speed in order to perform high speed dubbing, the PLL circuit is less likely to enter a locked state than when a CD is played back with a normal speed.
It is considered that this arises from the fact that, for example, when a disk is rotated at a high speed, the disk whirls in a shorter period with regard to a radial direction of the disk which is caused by eccentricity of the disk, and this deteriorates the follow-up performance of tracking servo control. Further, a CD is driven to rotate while it is fixedly held at a central position thereof by a chucking mechanism. However, when a CD is driven to rotate at a high speed, the holding force by the chucking mechanism does not sufficiently effectively work, resulting in slip of the CD. Consequently, the linear velocity of the CD as viewed from the optical head side varies. Also this is considered to be a cause of the phenomenon described above.
Further, a CD system involves error correction in which codes called CIRC are used. It is assumed here that high speed reproduction, for example, at a double speed is performed while a normal speed is used for a system clock signal for a signal processing system for playback of a CD. In this instance, the error correction processing of the CD system is limited from the arithmetic processing speed of the signal processing system such that, whereas double correction processing is performed for the C
1
parity and quadruple correction processing is performed for the C
2
parity upon normal speed reproduction as well known in the prior art, double correction processing is performed for the C
1
parity and double correction processing is performed for the C
2
parity upon double speed reproduction.
Consequently, the error correction ability is deteriorated more upon high speed reproduction than normal speed reproduction by a same disk defect such as a damage, a foreign article or the like to a CD. Also this deteriorates the stability of a reproduction operation.
A system which plays back, for example, a CD performs interpolation processing if a result that error correction according to the C
2
parity is NG is obtained as well known in the prior art. However, since data obtained by the interpolation have values different from those of an actual audio signal waveform, depending upon a result of the interpolation or the duration of a period within which the interpolation is performed, the data may possibly sound as interpolation noise.
Accordingly, in high speed dubbing which involves high speed playback of a CD, since a reproduction operation of a CD is rendered unstable from such reasons as described above, also interpolation noise is liable to be generated. Therefore, for example, when sound recorded on a MD by high speed dubbing is reproduced, there is the possibility that such interpolation noise as described above may sound to such a degree that it cannot be ignored. In this manner, in high speed dubbing, since at least a reproduction operation of the reproduction (CD) side which performs multiple speed reproduction becomes unstable, there is the possibility that the quality (sound quality) of data recorded by dubbing cannot be secured.
A possible countermeasure against this is, for example, as a countermeasure based on a determination of a user, to perform high speed dubbing and, if significant interpolation noise is included in a result of the recording, perform recording by a normal speed dubbing operation. However, even if noise is included in recorded sound, normally it is difficult for an ordinary user to discriminate whether the noise is interpolation noise or noise originating from some other cause such as, for example, a fault of the recording side.
Another possible countermeasure is to adopt, upon high speed dubbing, a higher speed as the set speed of the system clock signal corresponding to the reproduction multiple speed in order to augment the error correction capacity described above. However, this gives rise to another problem that, since unnecessary radiation according to the system clock signal of the increased speed increases, an additional cost is required for a countermeasure against radiation noise.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a recording and reproduction apparatus, a reproduction apparatus, a recording and reproduction method and a reproduction method by which interpolation noise of reproduced information is reduced and a recording medium on which information of higher quality is recorded can be produced.
In order to attain the object described above, according to the present invention, there is provided a recording and repro
Dinh Tan
Sony Corporation
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