AU639762B2

AU639762B2 - Recording /reproducing digital data

Info

Publication number: AU639762B2
Application number: AU73450/91A
Authority: AU
Inventors: Ernst F Schroder
Original assignee: Deutsche Thomson Brandt GmbH
Current assignee: Deutsche Thomson Brandt GmbH
Priority date: 1990-03-12
Filing date: 1991-03-02
Publication date: 1993-08-05
Anticipated expiration: 2011-03-02
Also published as: HK50496A; CA2076385C; JPH05505275A; JP2007242234A; AU7345091A; ES2069282T3; HUT64430A; CA2076385A1; ATE117120T1; JP2010182418A; FI924086A; DE4007814A1; JP3986552B2; DE59104275D1; HU216451B; WO1991014265A1; JP4543399B2; FI924086A0; KR100208909B1; FI111108B

Abstract

In conventional recording processes, the digital data are recorded continuously from the beginning to the end of the track of the recording medium at a net data rate which is fixed in each case for the entire recording. The aim of the invention is to record and/or scan data on a recording medium with optional reading and writing access. Continuous recording of digital data is replaced by burstwise recording. As a result of the burstwise recording of the data, each burst forms a cluster on the record carrier. The data are preferably recorded in CD standard recording format at a data rate of 1.411 Mbits per second. Recording and reproducing of data on a re-recordable contactlessly scannable record carrier, for example a magneto-optical disk (MOD).

Description

W091/14265 1 PCT/EP91/00389 Process for recording and/or reproducing digital data on a record carrier (recording medium) Contactlessly scannable rotating record carriers (recording media) such as a compact disk (CD) or magnetooptical disk (MOD) are suitable for storing digital data, preferably digital audio or video data, in large quantities.

These record carriers have, preferably, a spiral-shaped (helical) track. During the recording or playback operation, the record carrier rotates in such a way that the track passes by a radially adjustable scanning recording unit or scanning playback unit (laser) with a constant path velocity (standard for CD: 1.2 A CLV (constant linear velocity) system in the recording or playback device ensures that the constant path velocity is maintained.

With recording techniques used up until now, the digital data are recorded continuously from the start of the track to the end of the track on the record carrier, using a net data rate established, respectively, for the entire recording. This has the disadvantage that for recording data on a record carrier, the corresponding data must also be continuously made available (this can be realized through master tapes). As this is not always possible for the large memory capacity of such record carriers, the individual recording of data is limited.

With standard audio recording in the CD format, the data rate is 1.4112 Mbit/s 16 bit (per scanning value) 44.1 kHz (standard scanning frequency for CD) 2 (for 7- WO91/14265 2 PCT/EP91/00389 stereo)). With a net data rate of such a large size (net data rate is the data rate which is needed to store, transmit, etc., for example, one second of sound information or one second of picture information), playback times of about 60 min can be achieved per record carrier. To lengthen the recording time and hence the playback time, while keeping the same scanning frequency and recording in stereo, there are data reduction processes known which do not record all 16 bits per scanning value at the output of the analog-to-digital converter. For example, NIC (near instantaneous companding), MSC (multi-adaptive spectral audio coding), DPCM (differential pulse-code modulation), ADPCM (adaptive differential pulse-code modulation) or delta modulation are to be mentioned in this context; these techniques allow data reduced sound recordings without severe loss of quality when compared to standard CD recordings, whereby the playing time is extended to four hours per record carrier.

It is the object of the invention to guarantee, with optional reading and writing access, recording and/or scanning of data on a record carrier, This task is solved by the features listed in the first patent claim. Further advantageous developments of the invention result from the subclaims.

In principle, the conventional continuous recording of digital data is replaced by a burst-wise recording whereby each burst of data is, internally, continuously recorded.

Through using the burst-wise recording of data, each burst preferably forms a cluster on the record carrier. One burst of data means a fixed quantity of da'a, for example, one or more bits. A cluster is understood as a fraction of a track which essentially contains one burst of data. A recording W091/14265 PCT/EP91/O?89 with such clusters is hereinafter referred to as "cluster recording." With this recording technique it is of no importance whether the data rate of the data to be recorded, in particular sound data, was reduced by means of one or various data reduction methods.

With the help of the "cluster recording" described below it is possible, inter alia, to perform the following modes of operation: 1. Data recording with optional reading and writing access to data, also with differing net data rates.

2. A long play 1 h) sound recording by means of a sound data reduction technique such as MSC.

3. An extremely long play (up to 84 h) speech recording.

The data are preferably recorded like in the CD standard recording format using the unchanged scanning speed of 1.2 m/s and the scanning frequency of 44.1 kHz and, therefore, the standard CD data rate of 1.411 Mbit/s, so that no modifications are necessary to the CLV system and the equalizer circuits of conventional recording and playback units.

Consequently, a recording of 1.411 Mbit on the record carrier which, for example, have been data reduced by means of the MSC technique, contains not information for just one second of sound recording like with the CD standard but, rather, information for approximately four seconds.

For this it is advantageous to provide the data to be recorded with an error protection code such as, for example, the cross interleaved Reed Solomon code (CIRC), to

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T r-, W091/14265 4 PCT/EP91/00389 interleave them prior to recording and, using a channel code, for example, an EFM (eight-to-fourteen modulation) code, to record them on the record carrier, whereby through the EFM code, the data are structured in EFM frames. Each EFM frame preferably contains 24 Bytes of wanted data.

It is advantageous if the track of the record carrier is spiral-shaped and preformatted with unambiguous position data, preferably by means of the ATIP method. Thereby. each burst of data and hence each cluster on the record carrier can be individually accessed in order to, for example, delete, rewrite or read, etc. the corresponding data. Such a data recording with optional reading and writing access has great advantages, especially for computers. An individual recording of, for example, sound data, is first made possible through this.

It is advantageous to so dimension the length of a cluster such that it corresponds to a whole number multiple of an ATIP block and hence, the whole namber multiple of an EFM frame. Consequently, the unambiguous allocation of an ATIP block and an EFM frame to a cluster is determined, thereby ensuring, above all, the unambiguous addressability of a cluster.

To improve an error-free recording, prior to writing a cluster CL2, the prior written cluster CL1 is preferably read again and in the case of a defective recording of cluster CL1, recorded anew, and the defective cluster marked in order to avoid a repetition and a playback of the defective cluster upon playing back the record carrier.

In the following the invention is more closely explained by means of an example illustrated in the drawing.

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W091/14265 5 PCT/EP91/00389 Fig. 1 shows a block circuit for recording a sound channel with MSC data reduction which is realized in a recording device.

After filtering out the analog signal by means of a low pa.-s 1 and scanning by means of a 16-bit analog-to-digital converter 2, scanning impulses each of 16 bits are available at the output of said converter ready for further processing. These scanning values always arranged into blocks are subjected to a Fourier transformation in a special arithmetic unit 3. The result is a set of 1024 spectral coefficients for each block, whereby said set could also be obtained, for example, using a digital spectral analyzer normally used in measurement technology. The rate and phase values are now multiple adaptive-coded in an MSC coder 4, i.e. significant coefficients are presented and transmitted with many bits (up to 14), less significant bits with only a few bits. Very small insignificant coefficients are set to zero and not transmitted. The "bits saved" in such a case are added to other significant coefficients which are then correspondingly precisely transmitted.

After the MSC data reduction, the digital data leave the coder 4 with 308.7 kHz and are fed to a parallel-toserial converter 5, the output of which is connected to the data input of an intermediate memory 6. While the read-in clock frequency of the intermediate memory is 308700 Hz, the read-out frequency is 1.4112 MHz. A 7/32 frequency divider 7 converts the 1.4112 MHz clock frequency to 308.7 kHz.

The intermediate memory is controled by a control 'init 8 which inter alia compares the current position date 14 on the record carrier 11 with the desired position date. The intermediate memory only signals, via the signalling line 13, "Data Ready" when at least as much data as is provided for the set desired burst is stored in the intermediate \h r. ft i W091/14265 6 PCT/EP9l/00389 memory 6. If the recording unit has reached its desired position, then read-out of the memory is activated via "Output Control" 12 and the corresponding burst of data is read out from the intermediate memory using the CD standard recording data rate of 1.4112 Mbit per second, provided with a CIRC error code protection (cross interleaved Reed Solomon code) in a Reed Solomon coder 9 and subjected to interleaving (code spreading). An interleaving memory (not illustrated) is disposed in the coder 9 for the interleaving. The chronological progression of the processing and recording of digital data is shown by a graphical representation in Fig. 1.

As a contactlessly scannable rotating record carrier 11, such as the MOD, can be burdened with various physical defects, which can never be entirely avoided during production of the disk, the audio signals to be recorded are coded according to this special coding procedure. The data coded in the Reed Solomon coder 9 are subjected to an EFM modulation (eight-to-fourteen modulation) in a modulator and recorded on the MOD with the help of this line code, whereby the data are structured by the EFM modulation into EFM frames. This is also the format used on the compact disk.

The recording is organized so that 24 bytes of wanted data 6 stereo scanning values each of 16 bits) are recorded in one EFM frame. As a result of the interleaving, the 24 bytes of data in one frame do not belong to neighboring scanning values of the input wanted data. The data belonging to adjacent scanning values are distributed over approximately 110 successive frames. This improves the error protection.

'VT 9> W091/14265 7 PCT/EP9l/00389 The scanning or reproduction of data on the record carrier is carried out, in principle, reciprocal to the recording.

The magneto-optical disk (MOD) 11 used here as a contactlessly scannable rotating record carrier comprises a preformatted helical track which contains data for characterizing an absolute position and for controling the scanning unit. The preformatting is carried out with the ATIP (absolute time in pre-groove) method. For this, the track is modulated horizontally and with a frequency (22.05 kHz) proportional to the audio scanning frequency.

This frequency also serves for synchronizing a CLV servo in the recording unit and/or playback unit. This frequency is, for its part, is phase-modulated in a biphase format with the ATIP data. The data rate which can be achieved through this is relatively low but is sufficient for recording absolute position data in the format described above.

ATIP information can be constantly read and output via signal line 14 to the control unit 8 during the writing and reading of data on the record carrier. With the MOD this is realized in that ATIP information is read by means of the read/write unit (laser) and can be evaluated via the tracking unit which also operates during reading and writing.

The time segment on the storage medium containing such ATIP information is called the ATIP block in the following.

The format on the MOD is so arranged that during an ATIP block, 98 EFM frames are recorded or read.

Therefore, yet unwritten locations of the preformatted track on a record carrier like the one described above can be accurately located with the help of ATIP. The accuracy for this is given by the number of EFM frames, in this case W091/14265 8 PCT/EP91/00389 with an accuracy of 98 frames. With an MOD of the described format and a scanning speed of 1.2 m/s (as with a CD), an EFM frame has a length of 136.05 microseconds and hence, an ATIP block 13.3 msec. or 1/75 sec.

A search procedure for to a certain ATIP block is always performed in that the preceding ATIP block is read. If this block is decoded, it is known that the desired block follows immediately and can now be read or written.

The search procedure runs as follows: 1. reading the current ATIP, 2. deciding whether now waiting for up to one revolution is sufficient or a jump is necessary, 3. jump command from the mechanical side, 4. reading ATIP at (possibly coincidental) target, deciding whether new track jumping is necessary for correction or only waiting for up to one revolution is necessary, 6. reading ATIP until ATIP The desired recording is carried out in that the digital data to be recorded, as mentiond above, are assembled in an intermediate memory 6 and output from this in bursts with the standard recording data rate for CD, i.e.

1.4112 Mbit/s. Each burst of data in the intermediate memory is continuously recorded on the record carrier in a respectively allocated cluster with a fixed number (each 98) of ATIP blocks and EFM frames. After this there is time to reposition corresponding to the downgraded net data rate.

If the intermediate memory is filled up again, the writing unit (laser optics and magnetic head) should again just arrivP at or be just in front of the end of the cluster written last. In nrder to be able achieve this, it is necessary that the number of frames per cluster is greater W091/14265 9 PCT/EP9l/00389 than or equal to the product of reduction factor K and maximum number of frames per revolution (with a CD approx.

2220 at the outside). With the MSC data reduction, the reduction factor K is 0.25 and the number of frames per cluster should, therefore, be at least a bit larger than 555.

Owing to the unambiguous addressability via ATIP, the length of a cluster is a whole number multiple of the ATIP length.

If the recording stops at any random point, then the CIRC coding part, because of the code spreading (interleaving), contains data in the interleaving memory, contained in the Reed Solomon coder 9, which belong to those already recorded. In this case the coding part can be halted and then started again upon writing the next cluster, thereby writing the remaining data into the start of the next cluster.

This is not always easy to put into practice because stopping the hardware is not always possible immediately and because there is a danger of an imprecise linking of the data.

Therefore, a current cluster is not filled completely with wanted data but instead, it the coding of the wanted data, according to the interleaving length, is terminated before that and then, at the end of the cluster the interleaving memory is just emptied.

Besides the consequences arising from the interleaving it should be taken into account that at the start of the recording procedure for one cluster, the scanning unit or the read/write unit is switched over from read to write.

However, this scanning unit (laser) cannot always perform <3 P W091/14265 10 PCT/EP91/00389 this very rapidly and accurately. Therefore, at the start of a cluster, some data is frequently lost. It is for this reason that some dummy (empty) data is written at the start of a cluster, in this case 1 to 3 EFM frames.

In order to keep small the loss of dummy data at the start and, through emptying the interleaving memory, at the end, which appears in every cluster, a cluster is, therefore, not necessarily kept as short as possible. Owing to the necessary organization of a directory for the recorded data and the intrinsic flexibility of the record carrier, which of course should not be eliminated through cluster recording, the length of a cluster is also not arbitrarily long.

The following cluster length IcL is defined here for the MOD 13 with cluster recording: ICL 1176 EFM frames 12 ATIP blocks 0.16 sec.

The distribution within a cluster is as follows: Number of EFM frames Content 1 link frame 2 run-in 1029 data 111 interleaving 2 run-out 1 link frame unused This design means that 24696 bits of wanted data are recorded in one cluster, actually taking the space of 28224 bits. The loss in storage capacity is 1/8 12.5 per cent.

W091/14265 11 PCT/EP91/00389 A further consequence of this special selection specified above is that the clock frequency of the reduced wanted data is in a simple ratio to the "normal CD" clock frequency: 1/4 7/32.

The gross data rate which may be recorded is reduced by cluster recording to 1/4 as desired, but only 7/32 of the standard date rate is available for the net rate owing to the 1/8 loss.

Therefore, the net data rate which can be achieved in the above case is: 7/32 1.4112 Mbit/s 308.7 kHz/sec.

This corresponds to specifying a quantization with bit/sample, a rate which is very realistic when using modern data reduction techniques such as MSC being used here. Owing to the simple dividing ratio of 7/32, a simple synchronization of external, data-reduced sources with the record carrier is also possible with the described design.

To summarize, cluster recording means, therefore, that the wanted data is not recorded in a continuous sequence of 7350 EFM frames per second each with 24 usable bytes like with the normal CD format. Instead, the recording is carried out in clusters which in fact consist of a continuous sequence of a certain number of EFM frames, but that between the clusters the recording is not continuous.

A result of this is that each cluster can be optionally accessed for reading and, in particular, also for writing with ,ut the information recorded in the preceding or following clusters being disturbed.

I

W091/14265 12 PCT/EP91/00389 For optional writing access to a cluster, no special measure is necessary for the rapid running-up and runningdown of the laser because of the sufficiently long gaps.

After writing a cluster there is a pause which is used to position the start if the next cluster. In order to find the start of the next cluster, the ATIP blocks at the end of the next cluster are decoded. It is possible, therefore, to position it so that the entire final cluster is read once again before the one directly next is written again. This allows recording errors to be established and then break off the recording procedure completely in the case of too many errors or at least give a warning to the user.

Following up on the idea of error recognition, error correction is provided in addition. For this, the data of the last cluster is maintained in the intermediate memory.

There are two conceivable strategies for error correction: Firstly, it is repositioned to the start of the defective cluster and then the data for this are written once again. Directly after this follow the data of the following cluster. However, time is used for the positioning so that the pause between two writing cycles is possibly not large enough for positioning, correction reading, repositioning and correction writing.

As a recording error can also be linked with a flaw on the record carrier, it is better, in the case of an error, to rewrite the data from the defective cluster into the following cluster and the actual following data into the then following cluster. The defective cluster is then marked so that it can be simply omitted (jumped over) upon reading-out.

W091/14265 13 PCT/EP9l/00389 The marking is carried out in the directory UTOC (User Table of Content) of the record carrier or in a special cluster at the start and finish of the current continuous cluster recording. It is also possible to so mark (for example, a different synchronization word) the following cluster, rewritten for correction, so that with thereby an error in the preceding cluster is indicated. This means, however, that upon playback, one cluster must always be read out in advance.

Data recordings from computers on the basis of an operating system such as MS-DOS are carried out in blocks of 1024 bytes. If a cluster corresponding to the above details is designed, then 24 blocks with 1024 wanted bytes, possibly with additional bits for error protection, can be recorded without any problem in one cluster with at least 1029 usable EFM frames. As the addressability is also provided, cluster recording is, therefore, also suitable for data recording in a computer.

Owing to the piece-by-piece recording for the duration of 0.16 sec. and the subsequent pause of 0.48 sec. until the recording of the following cluster, a positioning strategy is provided because it cannot be assumed that the laser is located, of all places, at the start of the next cluster after the pause has expired.

One possible strategy, to be explained in the following, should make clear the logical course of events; in practice though, a deviation from this is certainly possible.

The data Lupplied by the MSC coder 4 of the sound data reduction method with 308.7 kBit/s are, as mentioned above, portioned in the intermediate memory 6 or a dual buffer.

The read-in clock frequency is 308700 Hz and the read-out '-c W091/14265 14 PCT/EP91/00389 clock frequency is 1411200 Hz. The length of the two buffers is each 197568 bits 24696 bytes.

Writing of the first cluster is started at ATIP After writing 1143 EFM frames, the writing process is concluded. After the waiting time of 0.48 sec. which now follows the dual buffer will signal "Data ready". k search procedure is now performed on the block at ATIP For this, a maximum of four tracks must be jumped over moving towards the inside. In addition, a waiting time of max. one revolution may become necessary. Now the next cluster can be written and so on.

Up to 400 msec. are available for the complete positioning. The positioning must be reliably completed within this time.

It can be assumed that a jump to the next neighboring track on the inside can be performed with great reliability.

Therefore, the following strategy is also possible: Writing of the first cluster is started at ATIP After writing 1143 EFM frames, the writing process is concluded. Directly after this a jump by one track towards the inside is made and a search procedure according to ATIP (n+12) instigated. This is repeated until the intermediate memory 6 signals "Data ready". When ATIP (n+12) is found again the writing procedure for the second cluster begins. After this writing procedure has finished there is then another jump of one track towards the inside and again a search procedure for ATIP (n+12) and so on.

The advantage with this strategy is that the jumps will always be only by one track although the procedure must take W091/14265 15 PCT/EP91/00389 place more frequently. The recording of the next cluster can begin at the latest one revolution after "Data ready".

If after writing the first cluster a search prgcedure for ATIP is run at first, i.e. after the start of the cluster just written, then the data just written can be read as a means of checking. An evaluation of the errors which have appeared can instigate suitable measures, for example, warning signals or display (f the error rate.

If upon the control reading, errors which cannot be corrected are detected, then a cluster at ATIP (n) recognized as defective can be rewritten at ATIP (n+12).

This is noted in a suitable manner in the UTOC (User Table of Content) so that the defective cluster at ATIP can be omitted during playback. The intermediate memory 6 is suitably constructed, for example, as a cyclic triple dual buffer in order to be able to execute the writing repetition described in the case of errors.

The method described above is not restricted to datareduction of data and a certain data-reduction technique such as the MSC used here. Likewise, a recording and reproduction with non-data-reduced data and/or with reduced data rates by means of other data-reduction techniques can be carried out on a record carrier.

One further possiblity of recording or reproducing data would be to record on to the record carrier or to read the data rate reduced by means of MSC burst-wise with the help of the intermediate memory and then, after a certain recording or playback time, to pause three times as long.

In this manner the record carrier can be filled to 25 per cent in one run. If one comes to the end, one can jump back again to the beginning during a 3/4 pause and fill or read a further 25 per cent of the disk in a second run and so on.

W091/14265 16 PCT/EP91/00389 This necessitates a difficult organization of the disk contents. The record carrier then contains either one just normal or one data-reduced program. The defined jump from the end to the start of the track is critical.

One fundamentally different possibility independently of the solutions described above would be to reduce the scanning speed corresponding to the reduction factor. If the wavelength on the record carrier remains the same, then with a reduction factor of 1/4 this would result automatically in a quarter of the recording data rate and a playing time four times as long. However, the CLV system must be switchable. Apart from that, the equalization circuits, for the signals coming from the record carrier, only receive signals with one-quarter of the normal frequency and must, therefore, be switchable. A mixing of "normal" recordings and data-reduced recordings on one disk is then only possible if a rapid switchover of the CLV by ,.he factor of one-quarter or four respectively is possible.

The invention can be applied equally to a recording and/or playback of digital data on a magnetic tape with PCM signals or a recording on a DAT (digital audio tape) in a DAT recorder. The organizational structure of a DAT recording can be established in an equivalent manner to the method described above with only slight modifications.

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Claims

2. Process according to claim 1, c h a r a c t e r i z e d i n t h a t a burst of data is recorded on the record carrier, independently of its 18 net data rate, always using the predetermined physical writing data rate.
3. Process according to claim 1 or 2, c h a r a c t e r i z e d i n t h a t each burst of data is recorded on the record carrier using the CD standard recording parameters or, respectively, CD standard recording data rate of 1.4112 Mbit/s. S 4. Process according to one of the preceding claims, c h a r a c t e r i z e d i n t h a t each burst of data is provided with at-least one address date for the position on the record carrier and/or each burst of data is provided with at least one address date for the position of the following burst of data. Process according to one of the preceding claims, c h a r a c t e ri z ed i n t h a t the data to be recorded are provided with an error protection code, preferably a Cross-Interleaved Reed-Solomon Code (CIRC) error protection code, and/or that the data to be recorded are subjected to an interleaving (code spreading), and/or that the data are recorded on the record carrier by means of a channel code, preferably an EFM code (eight-to-fourteen modulation), which structures the data in EFM frames respectively, whereby each EF!' frame preferably contains 24 bytes of wanted :data. 0
6. Process according to one of the preceding claims, c h a r a c t e r i z e d i n t h a t prior to writing a cluster, the cluster written previously is to read and/or in the case of a defective recording of a cluster, the recording is repeated in a following cluster, and/or that the defective cluster is marked. 19
7. Contactlessly scannable rotating record carrier, preferably a magneto-optical disk (MOD) or compact disk (CD) with at least one track for the recording of digital data, especially audio and/or video data which have been or are recorded by means of a process according to one of the claims 1 through 6, c h a r a c t e r i z e d i n t h a t the data to be recorded are recorded in bursts and that each burst of data is recorded in an associated fragment of the track, hereinafter referred to as a cluster, that the net data rate of the data to be recorded is reduced by using a data reduction technique and is smaller than the writing or reading data rate, that each burst of data is recorded, independently of its net data rate, using the same recording data rate, and that each burst of data is provided with an address date for the position on the record carrier and/or an address date for the position of the following burst of data.
8. Record carrier according to claim 7, c h a r a c t e r i z e d i n t h a t the track is helical and/or that the helical track of the record carrier is preformatted and contains data for identifying an absolute position on the record carrier.
9. Record carrier acccding to claim 8, c h a r a c t e r i z e d i n t h a t the helical track S is preformatted by means of an ATIP (absolute time in pre-groove) method and/or each position date preformatted using the ATIP method forms an ATIP block, the length of which corresponds to the recording length S" of preferably 98 EFM frames and/or that the length of a cluster corresponds to the whole-number multiple of an ATIP block length, preferably twelve times the ATIP block length. 20 Record carrier according to one of the claims 8 and/or 9, c h a r a c t e r i z e d i n t h a t the helical track is horizontally modulated, preferably using a frequency fprop proportional to the audio standard CD scanning frequency (44,1 kHz). Record carrier according to one of the claims 7 through 10, c h a r a c t e r i z e d i n t h a t the number of EFM frames per cluster is greater than or equal to the product of the reduction factor K of the reduction procedure and the maximum number of frames per revolution mmax of the rotating record carrier and/or that a cluster consists of at least 555 EFM frames, preferably 1176 EFM frames. Record carrier according to claim 11, c h a r a c t e r i z e d i n t h a t the 1176 EFM frames of a cluster are a combination of three EFM frames for the run-in, 1029 EFM frames for the wanted data, 110 EFM frames for the dummy (empty) writing of the interleaving memory, and 34 EFM frames remain unused or are for the run-out. Recording device and/or reproducing device for receiving a contactlessly scannable rotating record carrier according to one of the claims 7 through 12 and for executing the process according to one of the claims 1 through 6, c h a r a c t e r i z e d i n t h an intermediate memory controlled by a control unit for storing the data of one burst is provided in the recording and/or reproducing device, that the read-in clock frequency of the intermediate memory is different from the read-out clock frequency, that the frequency fprop proportional to the audio standard CD scanning frequency synchronizes a CLV (Constant Linear Velocity) system, whereby the S S S S. S S *SS S. 21 proportional frequency fprop is preferably phase- modulated in biphase format with the data, that the recording or scanning unit can be switched over from reading to writing at the start of the recording procedure for a cluster.
14. Recording device according to claim 13, c h a r a c t e r i z e d i n t h a t the data supplied by a coder for the data-reduction process is portioned in said intermediate memory whereby the intermediate memory is preferably constructed as a cyclic triple dual buffer. Dated this 25th day of May 1993 DEUTSCHE THOMASON-BRANDT GmbH Patent Attorneys for the Applicant F B RICE CO V* S ee B