JPS6080174A - Digital recording and reproducing system - Google Patents

Abstract

PURPOSE:To attain the digital dubbing to any of different data series by allocating the proper numerical value to one of actual designing conditions of a device and the common numerical value to other conditions respectively in terms of numerical values of different sampling frequencies. CONSTITUTION:Different sampling frequencies are decomposed into common and natural numerical values respectively, and the natural frequency is allocated to one of >=2 device designing conditions with the common numerical value allocated to other conditions respectively. Then the natural numerical value is varied in response to the sampling frequency. In this case, an error detection code consisting of a CRC code and a synchronizing code for identification of one frame is added to the data of 12 words as well as to a correction code of 4 words to define one frame. Then one equivalent track is formed with 160 frames for the sampling data series of 48kHz and with 147 frames for the sampling data series of 44.1kHz respectively. This track is allocated to a 1/4 track of an audio disk.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a digital recording and reproducing system, and in particular, the present invention relates to a digital recording and reproducing method, and in particular, the present invention relates to a digital recording/reproducing method, and in particular, the present invention relates to a digital recording/reproducing method, in which at least two or more data sequences having different amounts of data quantized at different adjacent sampling frequencies are recorded in the same digital The present invention relates to a digital recording and reproducing method for recording and reproducing using a recording and reproducing device.

[Description of Prior Art] A digital audio device is known as a conventional example of data sequences generated at different adjacent sampling frequencies. Such devices include, for example, digital audio discs (CA) that optically detect bits recorded on the disc and reproduce recorded audio signals.
D) devices and digital audio tuner devices using broadcasting satellites that are planned for the future. The sampling frequency of the former is 44.1kH2, and the sampling frequency of the latter is 48kl-
(Z is determined. Note that the number of quantization bits is 16 bits in both cases.

Furthermore, in the future, digital audio recorder MU
is expected to appear. This device is required to have a system that can perform recording and reproduction with the same operation for both data series of the two devices. Among these, there is a demand for something that is capable of digital dubbing, which is one of the characteristics of digital systems. However, such a device does not currently exist; for example, to generate a 4=11kHz data sequence from a 43 to 1z data sequence, it is common to use a sampling frequency conversion device. be. This device requires a high-speed, high-precision digital filter using a high-speed multiplication/division circuit, so it has a significantly high
1i and cannot be used as a device in the consumer field.

Furthermore, since the purpose of the user is to record and reproduce high-quality audio signals, the existence of a sampling frequency and the necessity of mutual conversion between them are 1! J! Therefore, even if an inexpensive sampling frequency conversion device appears, there is no need for a device that cannot perform any functions by itself.

However, even if a user is not required, technically equivalent functional means are required to realize complete data recording and reproduction.

Conventional digital recording and reproducing methods are configured to select one of the different sampling frequencies and completely process only that data series, but have the disadvantage that they cannot handle other data series. had. There are two solutions to this problem: using a sampling frequency conversion ratio, or interconnecting devices in an analog signal state. However, the former method is expensive, and the latter method suffers from deterioration in sound quality due to the fact that it is not digital dubbing.

[Summary of the Invention Therefore, the main purpose of the present invention is to decompose different sampling frequencies into respective common values and respective unique values, and to assign the unique value to one of two or more device design conditions. , assign a common numerical value to other conditions,
It is an object of the present invention to provide a digital recording and reproducing method that can be processed by the same recording and reproducing apparatus by varying the characteristic value in accordance with the sampling frequency.

The object and other objects and features of the present invention will become clearer from the detailed description given below with reference to the drawings.

[Embodiments of the Invention] Fig. 1 shows an example of the case where the present invention is applied to an audio disc, and Fig. 2 is a diagram showing the data structure of one track in the audio disc to which the invention is applied.

Next, this invention will be explained with reference to FIG. 141 and FIG. For example, set different sampling frequencies to 44.1
Assume kHz2 and 48kHz. Generally, audio has a two-channel configuration to make it stereo, with one sample and one channel.
If i11 (16-pit quantization) is one word (hereinafter abbreviated as W), then 8B, 2kW, and 961tW need to be transmitted or recorded and reproduced per second, respectively. If this condition is satisfied, there is no r)C1. ．． 20k)!
It is possible to realize a digital audio @shape that has the m-range of z and has S/N characteristics of 90 dB or more.

Now, the greatest common divisor of the two numbers above is 600,
If each is expressed using the greatest common divisor, it becomes 88200-600x147 96000-600x160, which is expressed as the product of the common a and the unique value that changes depending on the sampling frequency.

Therefore, by determining these two numerical values in accordance with the conditions for realizing the actual device, it is possible to create a recorder device that can process data sequences of two sampling frequencies. A conceivable example of such a recorder device is one employing a two-head helical skillen system. This method is currently in practical use in VTR equipment, and the major difference is that VTF (devices record and play back video signals by FM modulating them, whereas in the case of audio A, for example, M
We assumed a device that recorded and played back using a digital direct modulation method such as FM modulation. In this case, how many tracks are made up in 1 second? 4-track mechanism and τj running (including 1 system) (must be determined. For V-r R equipment, N-cho SC or PAL system is used. It is uniquely determined to be 60 tracks or 501-racks based on the television signal, but in the case of audio A, there is no such restriction.

By the way, this number of trunks is linked to the I\rad rotation speed, and this variable means changing the rotation speed, which complicates the control of the servo system and achieves stable running performance at a low cost. Since there is a problem in doing so, it is necessary to fix the number of l/racks. Next, consider the data arrangement conditions within the track. There are various causes of data errors in transmission media, such as scratches, dust, expansion and contraction of the medium, etc. Even if an error occurs due to these reasons, an error correction code is added to the audio data and recorded in order to completely restore the recorded data, and during playback, data errors are detected from the positive code. If an error exists, correct it. To realize this error correction, M words of correction code @1.2 are added to N words of audio data as shown in Figure 2, but this ratio is generally M/N less than 0.5. This is called code redundancy, and if the correction ability is the same, the smaller the number, the better the code. For example, in a DAD device, the number is N-12, M-4, and the redundancy is 0.33.

By the way, if we consider the case where these are variables, N-1
60 or N-147, and the number of words becomes significantly large, making it difficult to realize sufficient correction ability, including the actual hardware configuration. Therefore, the word structure of the error correction code must also be fixed.

Next, if one frame consists of (N+M) words, then one track will consist of P frames.

There are no particular restrictions on using P as a variable, as long as usage efficiency within one track is not an issue.

To summarize the above considerations, the number of recorded and reproduced words per second
The following holds true: X=TXPXN (where T is the number of tracks). Among these, the number of tracks T and the number of words in one frame N are fixed, and are assigned the previous greatest common divisor. That is, if TXN=600, it will inevitably become P-160 or P=147. Next, the values of T and N are integers, and there are several combinations of them, but the king's value is 60.
With the above, there is a problem that a lot of noise is generated when the head runs, and if the head is small, the running becomes unstable, so T-50 or 60, which are currently in practical use, are preferable.

At this time, N-12 is also 10, but the number of words N and the correction code M are interleaved at a predetermined distance in order to randomize the error appearance state. For this reason, a RAM with a predetermined capacity is used, but since the address of the RAM is controlled manually, N+M-2K is desirable from the viewpoint of RAM usage. As a combination that satisfies this, N=12, M
-4, -4 is obtained.

From the above explanation, N=12. The conditions of M-4 and T-50 are optimal. By the way, if N-12 cannot achieve a correction capability of "-", T=50°N-6, M-2,
ni=3. It is sufficient to set P=2X160 or P-2X147. At this time, the common numerical value is set to 300. Considering the above explanation in an actual device, for example, an error detection code consisting of 12 words of data, a 4 word correction code, a synchronization code for identifying one room, and a CRC code is added as shown in Figure 2. Added to make 1 frame, 48k
In the case of a Hz sampled data series, it is 160 frames,
Further, in the case of 44.1 kHz, 147 frames 'C equivalent 11-racks are formed respectively, and these equidistant 11-racks are, for example, 1.1 of an audio disc as shown in FIG. /41-assign to rack. If 50 such 1-rack tracks are used, the required audio signal for 1 second can be recorded and reproduced. At this time, 160-'+4
7 = 13 frames of redundancy may occur in one usage, but it is possible to sample by simply increasing the redundancy of the magnetic tape by 13 frames without using a sampling frequency conversion device etc. Frequency conversion 1! It has the advantage of being able to achieve the same functionality as a conventional device, and can be used as a consumer device in just one minute.

In addition, in the above explanation, the greatest common divisor of the two @bets is 600.
However, the present invention is not limited to this, and the common divisor 300 may be used, the -C1 common number drops may be set to 300, and the unique numbers may be set to 294..320, respectively.

[Effects of the Invention] As described above, according to the present invention, two different seed frequencies are decomposed into a common number and a unique number, and each number is calculated based on the actual device design conditions. Since we adopted a recording and reproducing method that assigns a unique numerical value to one condition and a common numerical value to other conditions, it is possible to digitally dub any of the arter sequences with two different sampling frequencies. It would be possible to obtain an inexpensive recording/reproducing device based on the Pi.

[Brief explanation of drawings]

FIG. 1 is a diagram C showing an example of the case where the present invention is applied to an audio disc. FIG. 2 is a diagram showing the data structure of 11-racks to which the present invention is applied. Agent Masuo Iwa Procedural amendment (voluntary) to the Commissioner of the Japan Patent Office 1, case description Japanese Patent Application No. 58-189000 2, name of the invention Digital recording and reproduction method 3, person making the amendment Representative Hitoshi Katayama Part 1 Agent 5, Claims column 1 of the specification subject to amendment 9 Detailed description of the invention 9
Brief description of the drawings, drawing 6, contents of amendment (1) The scope of claims of Akira tIon is as attached. (2) Correct the sentence ``In addition, the user must have a functional means...'' in lines 8 to 15 on page 3 of Akira@n et al. However, technically equivalent functional means are required to achieve complete gamma data recording and reproduction. 3) Ming Yuniku' @ page 4, line 19 to page 5, line 2 [Figure 1 is not shown. ” has been corrected to the following sentence. Figure 1 shows the format in which magnetic tape is used when the rotary head type helical scan recording and reproducing technology, which has been put into practical use in VTR1Fi equipment, is applied to a digital audio recorder. FIG. 3 is a diagram showing a data arrangement per one scanning track shown in the figure. (4) Specification vs. 9th paragraph, line 14 to page 10 □ Correct the sentence "The above explanation may be..." in line 17 to the following sentence. Considering the above explanation in an actual situation, as shown in Figure 2, for example, 6 words of data and 2 words of 1 correction code are combined with a synchronization code and CRC code to identify 1 frame. An error detection code of
One track is formed in each frame, and this one track is arranged on an audio tape, for example, as shown in FIG. The signal can be recorded and played back.At this time, redundancy for 320-294-26 frames may occur, but the magnetic tape can be recorded without using a sampling frequency converter or the like. redundancy of 26
It has the advantage that it can achieve the same function as a sampling frequency converter by just adding one frame, and can be used as a device for the general public. Note that in the above explanation, the common divisor of the two numbers is 3]0, but the total divisor is not limited to 600.
, the common number may be 600, and the important numbers may be 147 and 160, respectively, which can be arbitrarily set in consideration of the 11 total condition. (5) On page 11 of the specification, lines 8 to 9, "Figure 1 is a diagram showing..." is revised to the following sentence. FIG. 1 is a diagram showing one example of the format in which the magnetic tape of the present invention is used. (6) Figures 11 and 2 of the drawings are attached to the attached sheet. Above 2, Claims: In a digital recording and reproducing system in which two data sequences generated at different sampling frequencies that are close to each other are recorded and reproduced by the same digital recording and reproducing device, the specific sampling frequency is set as a common value for each. Decompose each unique value into unique values, assign the unique set to one of the two or more device design conditions, assign the common value to the other conditions, and set the unique value to the sampling frequency. A digital recording and reproducing method characterized by being variable in response to the

Claims (1)

[Claims] In a digital recording/reproducing method in which two data sequences generated at different sampling frequencies that are close to each other are recorded and reproduced using the same digital recording/reproducing device, the specific sampling frequencies are decomposed into their respective common numerical values and their respective unique numerical values. The natural frequency is assigned to one of the two or more device design conditions, the common value is assigned to the other conditions, and the unique value is varied in accordance with the sampling frequency. A digital recording and reproducing method that is characterized by: