CA2083615C

CA2083615C - Data recording/reproducing apparatus capable of simultaneously performing both reproducing and recording from and in a single recording medium

Info

Publication number: CA2083615C
Application number: CA002083615A
Authority: CA
Inventors: Shigemi Maeda; Kunio Kojima; Jun Akiyama
Original assignee: Sharp Corp
Current assignee: Sharp Corp
Priority date: 1991-11-28
Filing date: 1992-11-23
Publication date: 1996-04-23
Anticipated expiration: 2012-11-23
Also published as: EP0544299B1; DE69224159D1; KR930010880A; CA2083615A1; US5343452A; EP0544299A2; EP0544299A3; KR950007286B1; DE69224159T2; JPH05151758A

Abstract

A data recording/reproducing apparatus uses a single recording medium in which absolute address data have been previously formed. Also, the data recording/reproducing apparatus has a first memory for recording and a second memory for reproducing. Audio data reproduced from the recording medium is stored in the second memory at a first transfer rate, and the audio data stored in the second memory is sequentially read at a second transfer rate lower than the first transfer rate for audio-reproduction. Meanwhile, audio data input from an external source is sequentially stored in the first memory at the second rate, and the audio data stored in the first memory is read at the first transfer rate for recording on the recording medium. The aforementioned reproducing and recording operations are alternately repeated. Thus, the data recording/reproducing apparatus allows an audio data recording operation to be concurrently performed during audio reproduction with the single recording medium.

Description

208~615 DATA RECORDING/REPRODUCING APPARATUS CAPABLE OF
SIMULTANEOUSLY PERFORMING BOTH REPRODUCING AND
RECORDING FROM AND IN A SINGLE RECORDING MEDIUM

The present invention relates to a data recording/reproducing apparatus utilizing a recording medium which allows digitized audio signals or the like to be arbitrarily recorded, for example, recordable compact discs.
Heretofore, there have been widely used so-called compact discs, in which continuous data such as musical data are recorded as digital signals by means of optically-detectable minute bits. The compact discs are adapted to playback by an optical disc player exclusively provided for playing them back.
Figures 13 and 14 are schematic views for explaining a signal format used in compact discs. As shown in Figure 13, one frame 101a of recording signals is composed of a frame synchronizing signal 101 b designating the head of the frame 101a, a subcode 101c designating additional data pertaining to primary data, and a data field 101d containing 24-byte data, whichis the primary data, and a parity code for error detection/correction added to the primary data. It is noted that the data field 101d is provided by an error detection/correction system in which CIRC (Cross Interleaved Reed Solomon Code) incomplete interleave is combined.
As shown in Figure 14, a sector 102a is made up of 98 of the frames 101a, and a subcoding frame 102c is made up of 98 of the subcodes 101c, designating a track number (for musical primary data, called music number), absolute address data on the disc, and the like.
The time length of the sector 102a is 1/75 sec., and therefore 75 sectors correspond to 1 sec. A sector number is given by min. - sec. - frame data (where the frame is in base-75 system), forming time data and position data increasing stepwise from the innermost circumference of the disc.
Further, a data field 102d within the sector 102 is composed of 2352-bytes of primary data and 784-bytes of parity in a 98-frame architecture;
with audio data allocated to primary data, according to a compact-disc format, ;' ~ ,~L

a sampling frequency thereof is 44.1 kHz, quantization is by 16 bits, and the number of channels is 2 (stereo); therefore, the amount of data per second is:
(44.1 kHz x 16 x 2) = 1.4112 Mbits = 176.4 k bytes, and the amount of data per sector is:
(176.4 k bytes / 75) = 2352 bytes, which are allotted to the aforementioned primary data.
Figure 12 is a schematic view showing area locations on a compact disc. A compact disc 100 is made up of a primary data recording area 100b, which contains primary data, such as musical data, and sector numbers by means of the subcode, and a TOC (Table of Contents) area 100a where additional data pertaining to individual primary data recorded on the primary data recording area 100b are represented by the subcode. The additional data includes, for example, track numbers, recording-start sector numbers for individual tracks, and information for discriminating whether the track is allocated to audio data, such as music, or computer-oriented data. With the above-described format, a compact disc player reads the subcode data of the TOC area 100a at the time of the disc being loaded to recognize the amount of individual primary data (for musical data, corresponding to the number of music selections), the sector number of its corresponding recording-start position, and the type of data (audio data or other data). This allows desired tracks to be reproduced in prompt response to a subsequent reproduction instruction by an access operation that makes cross-reference between the data of the TOC area 100a and the sector number by the subcode of the primary data recording area 100b.
These compact discs are recorded with a constant linear velocity, or in the so-called CLV (Constant Linear Velocity) system in the recording mode, and therefore the resulting recording density is constant at any position on the compact disc, thus achieving enhanced recording capacities. In actual compact disc players, the rotation of a compact disc is controlled so that the time intervals of reproducing signals from the compact disc that has been CLV-recorded on the aforementioned signal format, for example those of the frame synchronizing signals, coincide with a reference time length, thereby accomplishing a CLV control.
From a different viewpoint, when such rewritable discs as magneto-optical discs that have been aggressively developed in recent years 5 are employed with various types of data, such as musical data or computer datarecorded thereon, it is desirable to offer such disc recordingtreproducing apparatus as is common in the reproducing system for conventional compact discs and is compatible therewith.
In such a case, especially in an initial compact disc that has not 10 undergone data recording, there exist no absolute address data using the subcode by the aforementioned signal format for the compact disc, or a frame synchronizing signal as employed for the CLV control, or other means.
Therefore, it is impossible to perform the access operation to any arbitrary sector prior to recording, or even do the CLV control needed during recording.
Thus, there has been proposed a system of recording absolute addresses equivalent to the absolute address data by the aforementioned subcode, in which an absolute address is biphase-mark modulated and thereafter the guide recess of an optical disc is shifted radially inward or outward of the optical disc or the width of the guide recess is changed, depending on whether each bit is "1" or "0" (see Japanese Patent Laid-Open Publication No. 64-39632).
With the above arrangement, if the frequency band for the absolute address in biphase-mark modulation and that for the recording data in EFM
(Eight-to-Fourteen Modulation) is differentiated from each other, it is possible to separate them from each other and reproduce them as such, and moreover to perform an access operation using the absolute address with the aid of the guide recess even for areas having no recording data. Besides, by using reproducing carrier components of the absolute address, an accurate CLV
control can be provided, which may be effected even during recording.
However, the above-described disc recording/reproducing apparatus using rewritable discs is capable of doing no more than recording A

208~615 during the recording operation, as is also the case with a tape recorder using compact cassettes which is the conventional data recording/reproducing apparatus of most common consumer use. Moreover, since the disc recording/reproducing apparatus is a single-purpose processing apparatus which works exclusively on reproduction during a reproducing operation, it can performneither concurrent reproduction for any other purpose during a recording operation nor concurrent recording for any other purpose during a reproducing operation.
For example, when the contents of a musical performance using a plurality of musical instruments are recorded and edited for each instrument, it is possible for sounds from one instrument to be played and recorded, and while that recording is being reproduced for verification by ear, another instrument is being played and recorded over top of the former. In such a case, however, there would arise the need for more than one recording/reproducing apparatus and for more than one recording media, involving increased location space and costs, as well as the need to operate the plurality of recording/reproducing apparatus simultaneously, with resultant degraded operability.
Indeed, there have been available business-use recording/reproducing apparati such as multi-track recorders, which have a number of recording channels and can perform recording and reproduction independently of each other for each channel, but they are very expensive and complex in operation due to their multifunction and thus do not lend themselves to regular consumer use.
Further, in so-called 'karaoke' systems, which are recorded instrumental music systems to accompany live singing and which are increasingly popular for household consumer use, it is often desired to record live singing with the reproduced instrumental accompaniment in a mixed arrangement. In this case also, there would arise the need for a recording medium and reproducing apparatus for reproducing the contents of the instrumental accompaniment, as in the above case, as well as the need for ~' 208361~

another recording medium and recording apparatus for recording audio data being mixed, both of the apparati necessarily being operated simultaneously and creating laborious work.
Moreover, it is undesirable that these playing-side recording 5 medium and recording-side recording medium exist separately, because complex work will be involved in the storage and control of such recording media.
The object of the present invention is therefore to provide a data recording/reproducing apparatus which solves these problems.
In order to achieve the aforementioned object, there is provided a data recording/reproducing apparatus for recording and/or reproducing audio data onto or from a recording medium having absolute address data, the apparatus comprising: a first memory for recording; a second memory for reproducing; a first reproducing means for reading audio data on the recording 15 medium by the block and storing them in the second memory at a first transferrate; a second reproducing means for sequentially reading the audio data stored in the second memory at a second transfer rate lower than the first transfer rate, and sequentially outputting them; a first recording means for sequentially storing audio data, which is inputted from an external source into the first memory at 20 the second transfer rate; a second recording means for reading the audio datastored in the first memory at the first transfer rate and for recording them in the recording medium by the block; and control means allowing a writing operation into the second memory by the first reproducing means and a reading operation from the first memory by the second recording means to be alternately 25 repeated.
In the data recording/reproducing apparatus according to the present invention, audio data reproduced from the recording medium are stored in the second memory at the first transfer rate, and the audio data stored in the second memory are sequentially read for audio-reproduction at the second 30 transfer rate lower than the first transfer rate. Meanwhile, audio data inputted from an external source are sequentially stored in the first memory at the - 208361~

second rate, and the audio data stored in the first memory are read at the firsttransfer rate for recording on the recording medium. The aforementioned reproducing and recording operations are alternately repeated. Thus, the data recording/reproducing apparatus allows an audio data recording operation to be 5 concurrently performed during audio reproduction.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
Figures 1A and 1 B are flowcharts, showing control of a concurrent recording/reproducing operation of a data recording/reproducing apparatus according to the present invention;
Figure 2 is a schematic plan view of a magneto-optical disc applied to the present invention;
Figure 3 is an enlarged plan view of a portion of the magneto-optical disc, showing grooves on the disc;
Figure 4 is a schematic view showing a primary data format within a sector;
Figure 5 is a schematic view showing a sector construction within 20 a block;
Figure 6 is a schematic view showing a block construction within a program;
Figure 7 is a timing chart showing data pertaining to a recording operation;
Figure 8 is a timing chart showing data pertaining to a reproducing operation;
Figure 9 is a block diagram of an embodiment of the data recording/reproducing apparatus according to the invention;
Figure 10 is a schematic view showing allocation rows of musical data to be subjected to concurrent recording/reproduction;

!A

Figure 11 is a timing chart showing data pertaining to the concurrent recording/reproducing operation;
Figure 12 is a schematic plan view of a compact disc for explaining the prior art;
Figure 13 is a schematic view showing a frame signal format of a conventional compact disc; and Figure 14 is a schematic view showing a sector format of a conventional compact disc.
The present invention is next described below based on an embodiment of a data recording/reproducing apparatus employing a rewritable disc, with reference to Figures 1 through 11.
Referring to Figure 2, a magneto-optical disc 1 as a rewritable optical disc includes a TOC area 1a for storing control data at the inner circumference, and a primary data area 1b occupying almost all the area outside the TOC area 1a.
The primary data area 1b records therein music data, while the TOC area 1a records therein additional data pertaining to various data stored in the primary data area 1 b. The additional data includes, for example, a list of music selections, start absolute addresses, and end absolute addresses, for each piece of the recorded data. The same signal format as shown in Figures 13 and 14 for the description of the prior art example can be used in the present case.
Referring to Figure 3, in the TOC area 1a and the primary data area 1b of the magneto-optical disc 1, spiral guide grooves 2, 2, ... (shown in 25 the hatched areas for convenience) are beforehand formed at specified intervals in the radial direction of the magneto-optical disc 1. The absolute addresses onthe magneto-optical disc 1 are, after subjected to biphase-mark modulation, defined by deviating the grooves 2, 2, ... radially inward or outward of the magneto-optical disc 1, depending on whether the bit is "1" or "0".
It is noted that the absolute address represents a position on the magneto-optical disc 1, and provides pre-recorded data as CLV rotation control data. Since an absolute address corresponds to one sector in the aforementioned compact-disc format, the absolute address is also referred to as a sector hereinafter.
Figures 4 through 6 show a data allocation example in the present invention based on the format as shown in Figures 13 and 14.
Figure 4 shows the format of the 2353-byte primary data portion of the sector construction shown in Figure 14, wherein a primary data field 103ais composed of a sector synchronizing signal 103b for discriminating the head of a sector, a sector address 103c for representing the address of each sector, and user data 103d.
It is noted that the sector address is, for example, of the same value as the absolute address data pre-recorded on the magneto-optical disc 1. In regard to byte organization, taking the one in CD-ROMs (Compact Disc-Read Only Memory) as an example, 12 bytes can be allotted to the sector synchronizing signal 103b and 4 bytes (referred to as header in CD-ROMs) can be allotted to the sector address 103c. Therefore, there can be used as user data per sector, (2352 - 12 - 4) = 2336 bytes.
Figure 5 shows the format of a block used for enabling the rewriting of data in the present embodiment, where a block 104a that is the minimum unit for the recording/reproducing operation is composed of only 15 sectors, sector 0 (104b) through sector 14 (104p).
Of these sectors, a group of sector 0 (104b) and sector 1 (104c) and another group of sector 13 (104O) and sector 14 (104p) are sector groups added for rewriting in the units of blocks. The reason for this arrangement is that, when an attempt is made to rewrite data on the above-mentioned compact-disc signal format, the data at a target sector position is distributed to the fore and hind sectors on the actual compact disc due to the CIRC incomplete interleave, making it difficult to rewrite only the target data (see Japanese Patent Publication No. 64-55787 for more detail).

9 208361~
Although recording data is fully continuous according to the CD
format, a large number of data errors take place at the start and end points of recording when rewriting is performed. In an attempt to effect the inherent CIRC correction capability, since the incomplete interleave code propagation length requires 105 frames, it is preferred to provide an additional 1.07 sectors, or essentially 2 sectors before and behind a sector composed of 98 frames.
Furthermore, the forward additional sector is also necessary as a lead-in area from the recording start point in PLL (Phase-Locked Loop).
Therefore, within the 15 sectors, each block 104a has two additional sectors allotted both before and behind the sectors in which user data are stored. Therefore, a data block 105 is allocated to the 11 sectors from sector 2 (104d) to sector 12 (104n), and the data block 105 may be given an amount of data equal to:
(2336 x 11 -. 25.7 k bytes - 206 k bits) Furthermore, Figure 6 shows an arrangement of the above-mentioned blocks in practical use for music data, where a program 106a corresponding to the one music selection is composed of a set of blocks in series, indicated as blocks B0 (106b) through Bn (106(n)).
Figure 9 is a block diagram showing an embodiment of the data recording/reproducing apparatus according to the present invention. The data recording/reproducing apparatus of the present embodiment comprises a spindle motor 4 for supporting and rotating the magneto-optical disc 1, an optical head 3 for throwing a laser beam onto the magneto-optical disc 1 for recording and reproduction, and a coil 24 for applying a magnetic field onto the magneto-optical disc 1 for recording. The present data recording/reproducing apparatus is so constructed as to perform recording in the so-called magnetic field modulation system and to allow new data to be overwritten on previously recorded data.
Referring first to the basic data recording operation, an analog signal inputted through an input terminal 18 is converted into a digital signal by an A/D (analog-to-digital) converter 19 and then supplied to a data compression processing circuit 20.
The data compression processing circuit 20 compresses digital audio data successively inputted from the A/D converter 19 according to a 5 specified algorithm, audio data having a sampling frequency of 44.1 kHz and a quantization bit number of 16 bits being compressed into that of 128 kbps per channel (practically 256 kbps for 2 channels in this case).
In greater detail, since data of 44.1 kHz x 16 x 2 . 1.41 Mbps is compressed into 256 kbps, a compression ratio of 256 k/1.41 M -. 1/5.5 is 10 obtained. For practical use, a variety of methods such as Audio spectral perceptual entropy coding, Adaptive transform audio coding, etc. introduced in "Sound Coding Algorithm and Standardization", by Shinji Hayashi, (The Transactions of the Institute of Electronics and Communication Engineers of Japan Vol. 89, No. 434, pp. 17-22) can be employed. However, since the 15 present embodiment is not limited to the contents of those methods, their descriptions are omitted.
The data compression processing circuit 20, besides the aforementioned compression processing, adds the sector synchronizing signal 103b and sector address 103c given by a controller 10 for each sector 20 according to the primary data format within each sector, as shown in Figure 4.
Thereafter, it generates additional sectors 104b, 104c, 104O, 104p as shown in Figure 5, and writes them into a first buffer memory 21 along with the compressed audio data as a compressed audio data block. Then the compressed audio data block is read at a required timing under the instruction 25 of the controller 10, and transmitted to a recording data processing circuit 22.
In the recording data processing circuit 22, CIRC error detection/correction parity is generated and added to the compressed audio data block derived from the first buffer memory 21. Further, subcode data derived from the controller 10 is added, and after EFM modulation is effected, 30 a frame synchronizing signal is further added to the audio data block, which is supplied to a coil driver 23. The coil driver 23 drives the coil 24 based on the 208361~

signal supplied thereto and at the same time, a laser beam is applied from the optical head 3 onto the magneto-optical disc 1, thereby accomplishing the recording of the signal.
In a basic reproducing operation, the signal reproduced in the optical head 3 is amplified in a reproducing amplifier 5 to supply a binary-converted magneto-optical signal Ps to a reproducing data processing circuit 9, while pre-recorded data is transmitted to a pre-recorded data detection circuit 6. The pre-recorded data detection circuit 6 is composed of, for example, a band-pass filter and a PLL to generate a PLL-synchronized clock to the pre-recorded data in the reproducing signal extracted from the band-pass filter.
Then a clock synchronized with the pre-recorded data composed of biphase-mark modulated absolute address data is supplied to a CLV control circuit 7.
The CLV control circuit 7 performs an accurate CLV control by comparing the synchronizing clock from the pre-recorded data detection circuit 6 with a reference frequency internally stored, and controls the spindle motor 4 with the resulting difference signal. The pre-recorded data in the reproducingsignal extracted by the pre-recorded data detection circuit 6 is supplied to an absolute address detection circuit 8.
The absolute address detection circuit 8, composed of a biphase-mark demodulator and an address decoder, performs a biphase-mark demodulation of the pre-recorded data extracted by the pre-recorded data detection circuit 6. Thereafter, the demodulated pre-recorded data is decoded by the address decoder into absolute address values which are position data on the disc 1, i.e. sector numbers, that are supplied to the controller 10.
In the reproducing data processing circuit 9, the frame synchronizing signal is separated from the binary-converted magneto-optical signal Ps in the reproducing signal supplied from the reproducing amplifier 5, and EFM-demodulation is performed to separate subcode data which is transmitted to the controller 10, while a CIRC error correction operation is performed using reproduced data parity.

A~

The reproducing data error-corrected by the reproducing data processing circuit 9 is written into a second buffer memory 14 as a compressed audio data block under the instruction of the controller 10, and then read underthe instruction of the controller 10 to be supplied to a data decompression 5 processing circuit 15.
In the data decompression processing circuit 15, sector address data is extracted from the compressed audio data block read from the second buffer memory 14 and is supplied to the controller 10. Meanwhile, the compressed audio data is treated for a specified decompression processing 10 (corresponding to the compression processing) and is sequentially supplied tothe D/A converter 16, thereby reproducing as outputs audio data restored in an analog form from a terminal 17.
The controller 10 receives recording and reproducing instructions of the user via an operating section 13 and sequentially displays a music 15 selection number, time data, and the like pertaining to recording and reproduction on a display section 12. The controller 10 has an access function for receiving absolute address data (i.e. a sector value) from the absolute address detection circuit 8 to recognize the position of the optical head 3 on the disc 1, and for moving the optical head 3 to a desired position by means of an 20 optical head moving mechanism (not shown).
The controller 10 also performs recognition of subcode data received from the reproducing data processing circuit 9. When a recognized subcode has the contents of the TOC area, the subcode is stored as control data in a TOC memory 11 and the control data is read from the TOC memory 25 11 as required. In recording, a sector address corresponding to absolute address data is supplied to the data compression processing circuit 20.
Meanwhile, absolute address data corresponding to the recorded primary data (musical data) is stored in the TOC memory 11. By supplying the contents of the TOC memory 11 to the recording data processing circuit 22 as subcode data 30 as required, control data is registered into the TOC area 1a of the magneto-optical disc 1.

The controller 10 also serves as a control means for writing and reading compressed audio data blocks into and from the first buffer memory 21 and the second buffer memory 14 in connection with the above-mentioned operations.
Figures 7 and 8 are schematic timing charts for explaining the basic recording and reproducing operations (in the case where each operation is performed singly) of the present data recording/reproducing apparatus.
These operations are described below with reference to those figures plus Figure 9.
Figure 7 shows an operation in the recording mode (recording only without reproduction), where (7A) depicts input data (a series of digital audio data before compression) of the data compression processing circuit 20; (7B) depicts compressed audio data blocks (a series of digital audio data after compression) which is outputted from the data compression processing circuit 20 and written into the first buffer memory 21; and, (7C) depicts compressed audio data blocks (compressed audio data blocks to be recorded) which are read from the first buffer memory 21 and outputted to the recording data processing circuit 22.
It is noted that the hatched portions in Figure 7 represent periods during which no data transfer takes place. Analog audio data inputted through the terminal 18 is continuous data, which is converted into digital audio data of 1.41 Mbps by the A/D converter 19. If the continuous data in this case is taken in correspondence to the blocks described later, as shown in Figure 7 (7A), each of the blocks A0(107a), A1 (107b), A2(107c), ... forms audio data 25 equivalent to approx. 0.8 sec., and that amount of data is:
(44.1 kHz x 16 bits x 2 channels x 0.8 sec.
= 1.12896 M bits) = 141.12 k bytes.
This series of pre-compression data is compressed into approx.
1/5.5 by the data compression processing circuit 20, resulting in an amount of 30 compressed audio data of:
(141.12 k bytes / 5.5) -. 25.66 k bytes.

-Further, the compressed audio data is combined with a sector synchronizing signal and sector address data as shown in Figure 4 and with additional sectors as shown in Figure 5, and the combined data are sequentially written into the first buffer memory 21 as compressed audio blocks B0(108b), B1 (108c), 5 B2(108d), ... starting at time point twl which has a slight delay in processing time from tw0, as shown in Figure 7 (7B).
It is noted that, in the compressed audio data blocks as shown in Figure 7 (7B), a sector synchronizing signal (12 bytes x 15 sectors) and sector address data (4 bytes x 15 sectors), and additional sectors (2336 bytes x 4 10 sectors) are added to the aforementioned compressed audio data per block (25.66 k bytes). The resulting total capacity of the block is:
25.66 k + (12 x 15) + (4 x 15) + (2336 x 4) . 35.2 k bytes, and the writing transfer rate into the first buffer memory 21 is:
((35.2 k bytes x 8 bits) / 0.8 sec) . 352.4 kbps.
On the other hand, referring to the compressed audio data block written into the first buffer memory 21, each time that block has been completely written therein as shown in Figure 7 (7C) (at tw2, tw4, ...), compressed audio data blocks B0(109b), B1(109d), ..., are read from the first buffer memory 21 20 and outputted to the recording data processing circuit 22, thus accomplishing recording along with the aforementioned sequence of operations.
It is noted that the memory reading rate in Figure 7 (7C) (equivalent to the transfer rate of recording data) is 1.41 Mbps, equal to that in conventional compact discs, and equivalent to a multiplying factor of the 25 aforementioned memory writing transfer rate of:
(1.41 Mbps / 352.4 kbps) . 4 times.
From the fact that each of the compressed audio data blocks B0(109b), B1(109d), ... on the magneto-optical disc 1 is composed of 15 sectors and that the time per sector is 1/75 sec., the above correlation results in:
(1/75) x 15 = 0.2 sec, which is:

A t 208~615 (0.8 / 0.2) = 4 times, as compared with 0.8 sec. that is the time occupied by the pre-compression audio blocks AO(107a), A1(107b), A2(107c), ..., equal to the aforementioned transfer rate ratio.
Accordingly, the actual recording operation is performed in a time of 1/4 with respect to the compressed audio data block time for one block, whilethe remaining 3/4 of the time is dedicated to standby. Thereafter, these intermittent recording operations are repeated to accomplish the recording of the continuous audio data inputted from an external source.
Figure 8 shows the operation during the reproduction (in this case, only reproduction without recording), where (8A) depicts a compressed audio data block which is reproduced from the magneto-optical disc 1 and written into the second buffer memory 14 from the reproducing data processing circuit 9;
(8B) depicts a compressed audio data block which is read out of the second buffer memory 14 and fed to the data decompression processing circuit 15; and (8C) depicts the post-decompression audio data rows outputted from the data decompression processing circuit 15. In addition, the hatched portion in Figure 8 represents an interval during which no data transfer takes place.
First, during a period from trO to tr3, as shown in Figure 8 (8A), compressed audio blocks BO(110a), .. , B3(110d) are written into the second buffer memory 14 at a time, and thereafter writing is interrupted. The reason for the interruption is that the capacity of the second buffer memory 14 is limited, and as far as Figure 8 is concerned, a case is presented where the buffer memory capacity is equivalent to 4 blocks, for simplicity of description.It is noted that the buffer memory writing transfer rate in Figure 8 (8A) is 1.41 Mbps, corresponding to that in the recording operation.
Simultaneously with this, in Figure 8 (8B), as the compressed audio data block BO(110a) has completely been written into the second buffer memory 14 at time point tr1, a read operation is started. The memory reading transfer rate of the compressed audio data block BO(111b) in this case is corresponding to that in the recording operation, being 352.4 kbps.

-Further, the audio reproduction after audio data decompression is effected by the data decompression processing circuit 15 starting the audio output after decompression at time point tr2, which has a slight delay in processing time from tr1.
On the other hand, when time point tr4 is reached, the compressed audio data block B0(111b) in Figure 8 (8B) has completely been read, leaving an empty space in the second buffer memory 14. Thus, as shown in Figure 8 (8A), the compressed audio data block B4(110f) is reproduced, that is, written into the second buffer memory 14, a standby state following thereafter again.
It is noted that the ratio between the writing transfer rate and the reading transfer rate into and from the second buffer memory 14 is:
(1.41 Mbps / 352.4 kbps) . 4 times, and therefore the actual reproducing operation is performed in a time of 1/4 of the compressed audio data block time for one block, while the remaining 3/4 time is dedicated to standby. Thereafter, similarly, each time an empty space arises in the second buffer memory 14, a compressed audio data block is intermittently read out of the magneto-optical disc 1 to be written (fed) into the second buffer memory 14, thereby accomplishing the reproduction of continuous audio data without interruption.
Figure 1 is a flowchart showing an example of the simultaneous recording/reproducing operation based on the above-described basic operations in the data recording/reproducing apparatus according to the present invention.
The example in the figure is such that, with respect to musical data of the primary data area as shown in Figure 10 (10A), control data as shown in Table 1 presented below is read from the TOC area 1a of the magneto-optical disc 1 and stored in the TOC memory 11. While the reproducing operation of the first music 10a is performed, the recording operation is simultaneously performed.
As shown in Figure 10 (10B), new musical data is recorded as the second music 10c, and the control data is updated and reregistered at the time of stopping the recording. The following description is made of this situation, in connection with the operational sequence diagram of Figure 1.

Table 1:

Music No. Recording-start Recording-end absolute absolute address position address position 01 01 min, 00 sec, 04 min, 18 sec, 01 frame 15 frame Specifically, in Figure 10 (10A), it is assumed that the first music 10a starts at [01 min, 00 sec, 01 frame], and ends at [04 min, 18 sec, 15 frame], and that the second music 10c, on the other hand, is recorded at a position following the end of the first music 10a at the same time the first music 10a isbeing reproduced.
With reference to the flowchart of Figure 1 and the operational sequence diagram of Figure 11, next described is the operation in the case of a simultaneous recording/reproducing operation, that is, the reproduction of thefirst music and the recording of the second music are performed in parallel. In Figure 11, (11A), (11B), and (11C) represent a sequence of signals pertaining 20 to the reproducing operation, where (11A) depicts the compressed audio data blocks reproduced from the magneto-optical disc 1 and written into the second buffer memory 14 from the reproducing data processing circuit 9, (11B) depicts the compressed audio data block read from the second buffer memory 14 and transmitted to the data decompression processing circuit 15, and (11C) depicts 25 the audio data decompressed and outputted by the data decompression processing circuit 15.
Also, (11D), (11E), and (11F) represent a sequence of signals pertaining to the recording operation, where (11D) depicts the audio data inputted to the data compression processing circuit 20, (11E) depicts the A~

compressed audio data block compressed by the data compression processing circuit 20 and thereafter written into the first buffer memory 21, and (11F) depicts the compressed audio data block to be recorded, which is read from the first buffer memory 21 and fed to the recording data processing circuit 22.
It is to be noted that in the following example of operation, delays of processing time of the data compression processing circuit 20 and the data decompression processing circuit 15, as shown in Figures 7 and 8, are omitted for simplicity of explanation.
In addition, the following description is based on the assumption that the first buffer memory 21 and the second buffer memory 14 have at least such capacities as can store 5 or more compressed audio data blocks.
When the simultaneous recording/reproducing instruction (hereinbelow, the contents of the instruction is assumed to be such that the first music is for reproduction, and the second music for recording at a position following the end of the first music) is given from the operating section 13 by a user and then sent to the controller 10 (S0), the controller 10 first sets the reproducing block pertinent address (Ap) to [01 min, 00 sec, 01 frame] read from the TOC memory 11. This is the recording-start position of the designated music, or in this case, the first music 10a (S1). The controller 10 also sets the recording block pertinent address (Ar) to [04 min, 18 sec, 16 frame], which is an empty space determined by the contents of the TOC memory 11 (S2).
It is to be noted that (Ap) and (Ar) represent the leading absolute addresses for each compressed audio data block that is to be the object of the reproduction and recording.
Next, the (Ap) position is accessed, i.e. the start of the first music at (S3); thereafter three blocks starting with the compressed audio data block pertinent to the (Ap) position are reproduced, to write them into the second buffer memory 14 (S4). Reading from the second buffer memory 14, starts at step S5, and the audio data of the first music 10a starts to be reproduced via the optical head 3, the reproducing amplifier 5, the reproducing data processing -circuit 9, the second buffer memory 14, and the data decompression processing circuit 15 through the D/A converter 16.
In correspondence with the timing chart of Figure 11, during the period from tO to t1 in Figure 11 (11A), compressed audio data blocks PBO(aO), 5 PB1(a1), and PB2(a2) are reproduced and written into the second buffer memory 14, corresponding to step S4. Thereafter, the compressed audio data block PBO(bO) starts being read from the second buffer memory 14, as shown in Figure 11 (11 B), and the decompressed audio data starts being reproduced with PAO(cO), corresponding to step S5. In the meantime, subsequent to (or in 10 parallel to) step S5, writing into the first buffer memory 21 is started (S6).
Specifically, as shown in Figure 11, at the time point t1 equal to the start of the audio data reproduction, audio input data RAO(dO) in Figure 11 (11D) is written into the first buffer memory 21 as a compressed audio data block RBO(eO) (Figure 11 (11E)).
Then, at step S7, the compressed audio data block pertinent address (Ap) that is to be subsequently reproduced is updated. Here, since the three blocks have already been reproduced at step S4, the address value is determined by adding another three-block equivalent, i.e. (15 x 3) = 45 sectors,to the current (Ap) value. That is, 45 sectors are added to [01 min, 00 sec, 01 frame], thus giving an updated reproducing block pertinent address (Ap) of [01 min, 00 sec, 46 frame].
Next, at step S8, it is determined whether or not reading the second buffer memory 14 has been completed by two blocks; if it has, then four blocks (60 sectors) are reproduced from [01 min, 00 sec,46 frame], which is the address of the compressed audio data block (Ap) being written into the second buffer memory 14 at step S9.
The decision to read the buffer memory at step S8 can be done by the sector address recognized by the data decompression processing circuit 15. As depicted by time points t1 to t3 in Figure 11 corresponding to the above-described steps S8 to S9, reading of the second buffer memory 14 starts at t1, as shown in Figure 11 (11 B). From the time point t2 at which two blocks, i.e.

the compressed blocks PBO(bO) and PB1(b1) have been completely read, writing to the second buffer memory 14 restarts, as shown in Figure 11 (11A).
Subsequently the compressed audio data blocks PB3(a3), PB4(a4), PB5(a5), and PB6(a6) are written.
Then the address (Ap) pertinent to the compressed audio data block to be successively reproduced is updated at step S10. Here, four blocks have already been reproduced at step S9, and therefore the address value is given by adding four blocks to the current (Ap) value, and (15 x 4) = 60 sectorsis added to [01 min, 00 sec, 46 frame], yielding an updated reproducing block pertinent address (Ap) of [01 min, 01 sec, 31 frame].
Then, an access operation is executed to [04 min, 18 sec, 16 frame], which is recording block pertinent address (Ar) at step S11. Thereafter it is determined whether or not the writing of four compressed audio data blocksinto the first buffer memory 21 has been completed; if it has, the four compressed audio data blocks are read out of the first buffer memory 21 at step S13, and are fed to the recording data processing circuit 22, accomplishing the recording.
Referring to Figure 11, following the time point t3 at which the writing of the compressed audio data blocks into the second buffer memory 14 has been completed in connection with step S9, the access operation to the recording block is started. From the time point t4 at which the writing of four blocks, i.e. the compressed audio data blocks RBO (eO), RB1 (e1), RB2 (e2) and RB3 (e3) into the first buffer memory 21 as shown in Figure 11 (11E) is completed, the compressed audio data blocks RBO(fO), RB1(f1), RB2(f2), and RB3(f3) from the first buffer memory 21 are read, as shown in Figure 11 (11 F), for recording at the pertinent position on the magneto-optical disc 1.
It is noted that the decision of whether or not the writing of four blocks into the first buffer memory 21 has been completed can be made from sector address data sequentially given to the data compression processing circuit 20 for each sector by the controller 10.

Next, the address (Ar) pertinent to the compressed audio data block to be successively recorded is updated at step S14. Here the four blocks have already been recorded at step S13, and therefore, the address value is given by adding four blocks, i.e. (15 x 4) = 60 sectors to the current (Ar) value.
That is, 60 sectors are added to [04 min,18 sec,16 frame], yielding an updated recording block pertinent address (Ar) of [04 min, 19 sec, 01 frame].
Then an access operation is executed to the [01 min, 01 sec, 31 frame], which is the address (Ap) pertinent to the reproducing block to be next reproduced at step S15. Thereafter it is determined whether or not the reading of four compressed audio data blocks from the second buffer memory 14 has been completed. If such reading has been completed, it is then determined whether or not there is a halt instruction given from the operating section 12 at step S17, if not, the program returns to S9 to repeat the same operations, thereby repeating intermittent reproducing and recording operations.
Referring to Figure 11, from time point t5 at which the compressed audio data blocks from the first buffer memory 21 are read (recorded) in connection with step S13, an access operation is executed to the address pertinent to the block to be successively reproduced. From time point t6 at which the reading is completed of four blocks, i.e. the compressed audio data blocks PB2 (b2), PB3 (b3), PB4 (b4) and PB5 (b5) from the second buffer memory 14 as shown in Figure 11 (11 B), the writing of compressed audio data blocks PB7 (a7), PB8 (a8), PB9 (a9), and PB10 (a10) into the second buffer memory 14 as shown in Figure 11 (11A) is executed.
On the other hand, when there is a halt instruction given from the operating section 12 at step S17, the program goes to S18 where recording-start and recording-end absolute address location data (corresponding to the second music that has been recorded, as described above) are updated (added) in the TOC memory 11. Then an access operation to the TOC area 1a on the magneto-optical disc 1 is executed at step S19, and thereafter the contents of the TOC memory 11 are recorded in the TOC area 1 a as new control data, thus ending a sequence of operations (S21).

2~83615 It is to be noted that in the above example of operation, the access operations at steps S11 and S15 are assumed to be completed within the periods from t3 to t4 and from t5 to t6, that is, within the 0.8 seconds that is the time required for one pre-compression audio data block in the present invention.5 However, when the invention is applied to any system having a poor access performance, the invention can be made applicable to such cases by increasing the storage capacities of the second buffer memory 14 and/or the first buffer memory 21.
Further, in the above example of operation, it is arranged that if 10 there is a halt instruction at step S17, the reproducing and recording operations are immediately halted. Alternatively, it may be such that, at least on the recording side, the compressed audio block which is left (not recorded) in the first buffer memory 21 is recorded, and thereafter the program reaches step S18.
In the manner described above, the operations are carried out repeatedly in the form of intermittent recording/reproduction with the compressed audio block using buffer memories, thereby allowing audio data after decompression and before compression to be reproduced and recorded without interruptions. Thus, it becomes substantially feasible to simultaneouslyperform reproduction and recording.
Although the above description has been made based on the compact disc format, yet the present invention is not limited to this. Instead, block and sector constructions may of course be in various forms, and moreover address data also may be applied in various forms.
Also, although the above-described embodiment has described the treatment of audio data, it is apparent that the present invention can be applied image data or other visual or auditory continuous data.
Further, although the present embodiment has described the use of compressed audio data, the present invention is not limited to this; however,it can basically only be applied in its various forms if there is a difference in data transfer rate between the write and read side of the buffer memory.

208361~

For example, taking the case of the above-described compact disc format, the present invention is made applicable to uncompressed conventional compact disc audio data (sampling frequency: 44.1 kHz; quantization bit number: 16 bits, number of channels: 2) per se, by increasing the line speed 5 of the disc beyond to its normal speed.
Furthermore, the present invention can be embodied not only in the optical disc apparatus used as a computer-oriented external storage device, but also in hard disks and floppy disks, and also with a magnetic tape recordingdevice, without departure from the spirit of the present invention.
As described hereinabove, the data recording/reproducing apparatus according to the present invention works such that audio data reproduced from a recording medium is stored in a second memory at a first transfer rate, and the audio data stored in the second memory is sequentially read at a second transfer rate lower than the first transfer rate for audio-reproduction. Meanwhile, audio data inputted from an external source is sequentially stored in a first memory at the second transfer rate, and the audiodata stored in the first memory is read at the first transfer rate for recordation on the recording medium. This allows the recording operation to be performed simultaneously with the audio reproduction.
Accordingly, it is possible that while desired music or the like being reproduced using a single data recording/reproducing apparatus and recording medium, different music or the like can be simultaneously recorded. Thus a data recording/reproducing apparatus having a new function and high added-value is provided.
Further, when the contents of singing in accompaniment to music, such as 'karaoke' previously prepared (recorded), are recorded, or when a mixing recording has over-recording for each instrument using a plurality of musical instruments, it is made possible with a single data recording/reproducing apparatus and recording medium, requiring reduced location space and providing low price and excellent operability.

Moreover, the fact that a single recording medium will suffice for such purposes provides another advantage, in that the recording medium can be improved in its storage and control.
Furthermore, it is possible to use, as a recording medium for such 5 purposes, so-called partial ROM discs in which the aforementioned accompanying music is previously recorded in pit form such as in compact discs with some portion of the disc exclusively dedicated to reproduction and the restthereof used as recordable area. New disc usage can be thus developed, and at the same time the user is relieved of the need for previously recording the 10 accompanying music, thereby further increasing the convenience of the system.The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within15 the scope of the following claims.

Claims

1. A data recording/reproducing apparatus for recording and/or reproducing audio data onto or from a recording medium having absolute address data, the apparatus comprising:
a first memory for recording;
a second memory for reproducing;
a first reproducing means for reading audio data on the recording medium by the block and storing them in the second memory at a first transfer rate;
a second reproducing means for sequentially reading the audio data stored in the second memory at a second transfer rate lower than the first transfer rate and sequentially outputting them;
a first recording means for sequentially storing audio data, which is inputted from an external source, in the first memory at the second transfer rate;
a second recording means for reading the audio data stored in the first memory at the first transfer rate and recording them in the recording medium by the block; and, control means for allowing a writing operation into the second memory by the first reproducing means and a reading operation from the first memory by the second recording means to be alternately repeated.

2. The data recording/reproducing apparatus as in claim 1, wherein the control means includes means for instructing simultaneous reproduction and recording operation.