JP2943194B2 - Digital data recording method - Google Patents

Description

The present invention relates to the recording of digital data such as digital audio data and digital video data on recording media such as optical disks, magneto-optical disks, magnetic disks, and other recording disks, and magnetic tapes. About the method.

[Summary of the Invention]

The present invention encodes a series of digital data so as to minimize DC unbalance, and adds pseudo data to the end of the encoded series of digital data and records the pseudo data on a recording medium. None, so that the DC unbalance at the end of the pseudo data of the encoded series of digital data to which the pseudo data is added is smaller than the DC unbalance at the end of the encoded series of digital data. Thus, the DC imbalance of the entire recording medium is prevented from increasing irrespective of an increase in the number of times of recording a series of digital data.

[Conventional technology]

When digital data is recorded on a recording medium, for example, a recording disk, a DC imbalance (DS
V: Digital sum variation) is recorded normally. In this case, the recording period includes a sector (block = 98 subcode frame = 2352 bytes, 2 Kbytes), a cluster (64 Kbytes), and the like.
Also, a recording period of any length is possible.

In the conventional example (1) of FIG. 7, the DC unbalance (DSV) is minimized in each of successive blocks (or clusters) N, N + 1, N + 2,.
That is, digital data modulated such that the DC unbalance at each start end is 0 and the DC unbalance at each end is +5, -3, -6, +3, -1 is recorded.

In the conventional example (2) shown in FIG. 8, DC is sequentially supplied to successive blocks (or clusters) N, N + 1, N + 2,..., N + 4 via a non-signal section (connection area) CN of a fixed length. Modulated so that the unbalance (DSV) is minimized, that is, the DC unbalance at each start is 0, and the DC unbalance at each end is +5, -3, -6, +3, -1. Digital data is recorded.

In the conventional example (3) shown in FIG. 9, a series of digital data A, B, and C each having an arbitrary length is converted into a DC unbalance (DC unbalance) via a non-signal section (connection area) CN having a predetermined length. DSV) is minimized, that is, the DC unbalance at each start is 0
Are modulated and recorded so that the DC imbalance at each end is +2, -1, and -2, respectively.

[Problems to be solved by the invention]

By the way, if a plurality of series of digital data modulated so as to minimize the DC unbalance is recorded on the recording disk, the DC unbalance in the entire recording disk becomes small, but each series of digital data is reduced. Is not always 0, so the sum of the last DC unbalance of each series of digital data is calculated when the positive or negative variation of each DC unbalance is biased to positive or negative. May increase in the positive or negative direction as the number of recordings of a series of digital data recorded on the recording disk increases.

In view of such a point, the present invention provides a method for recording a series of digital data, even if the series of digital data is encoded to minimize DC unbalance and recorded on a recording medium, regardless of the number of recordings of the series of digital data. An object of the present invention is to propose a recording method in which the DC imbalance of the entire medium does not increase.

[Means for solving the problem]

According to the digital data recording method of the present invention, a series of digital data is subjected to d-k modulation (where d and k are positive integers) and encoded, and the modulated k bits are converted to m bits (m bits). Here, m is a positive integer) and marginal bits are added to control so as to minimize DC imbalance. At the end of a predetermined block of a series of modulated digital data, pseudo data composed of (k + m) bits is added. In addition, control is performed so that the cumulative DC imbalance is reduced.

[Action]

According to the present invention, a series of digital data is encoded by performing dk modulation (where d and k are positive integers). Modulated k bits are replaced by m bits (where m
Is a positive integer) and control is performed so that the DC imbalance is minimized. Pseudo data consisting of (k + m) bits is added to the end of a predetermined block of a series of modulated digital data to control the accumulated DC imbalance to be small.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1, 2 and 3 (1),
(2) and (3) correspond to the conventional examples (1), (2) and (3) described in FIGS. 7, 8 and 9, respectively.

In the embodiment (1) shown in FIG. 1, in each of successive blocks (or clusters) N, N + 1, N + 2,..., N + 4, DC unbalance (DSV) is minimized.
That is, the DC unbalance at each start is 0 and the DC unbalance at each end is +5, -3, -6, +3, -1. Each of the pseudo data DM is added and recorded on the recording medium, and the DC unbalance of the encoded series of digital data to which the pseudo data DM is added at the end of the pseudo data is 0 (or (The absolute value is close to 0).

In the embodiment (2) of FIG. 2, each of successive blocks (or clusters) N, N + 1, N + 2,..., N + 4 via a non-signal section (connection area) CN of a fixed length, respectively. In order that the DC unbalance (DSV) is minimized, that is, the DC unbalance at each start is 0, and the DC unbalance at each end is +5, -3, -6, +3, -1. The pseudo data DM is added to the non-signal section (connection area) CN after each end of the modulated and recorded digital data and recorded on the recording medium, and the pseudo data DM is added. The DC imbalance at the end of the pseudo data of the encoded series of digital data is set to 0 (or a value whose absolute value is close to 0).

In the embodiment (3) shown in FIG. 3, a series of digital data A, B, and C each having an arbitrary length via a non-signal section (connection area) CN having a predetermined length has a DC unbalance. (DS
V) is minimized, that is, the DC unbalance at each start is 0, and the DC unbalance at each end is +2, -1, and -2, respectively.
The pseudo data is added to the non-signal section (connection area) CN after each end of the digital data which is modulated and recorded so that
DM is recorded on a recording medium, and the DC imbalance at the end of the pseudo data of the encoded series of digital data to which the pseudo data DM is added is 0.
(Or an absolute value close to 0).

The modulation method of the digital data in the embodiments (1), (2) and (3) of FIGS. 1, 2 and 3 employs EFM (8-14 modulation) employed in digital audio data on a compact disc. ), The fourth
As shown in FIG. 5, FIG. 5 and FIG.
One unit of pseudo data (1), (2), and (3) in which 3-bit margin bits "000", "100", and "010" are connected before bit information bits "01001000100000", respectively.
Is provided. If the DC unbalance (DSV) at the beginning of the recording waveform by NRZ-I modulation (encoding) of one unit of digital data in FIGS. 4, 5 and 6 is set to 0, the DC unbalance at the end ( DSV) is +1, -1 and -3, respectively. still,
Pseudo data (1), (2) in FIGS. 4, 5 and 6
The recording waveform obtained by inverting (3) and (3) is such that when the DC unbalance (DSV) at the beginning is 0, the DC unbalance (D
SV) is -1, +1 and +3, respectively.

The pseudo data (1) in FIG. 4 is used when the last bit of the digital data to be connected is "1".
The pseudo data (2) in FIG. 5 is used when the last bit of the digital data to be connected is “0”, and the pseudo data (3) in FIG. 6 is the last bit of the digital data to be connected. Is used when is “0”.

Note that the DC unbalance at the beginning of this one unit of pseudo data is zero.
In this case, the value of the DC unbalance at the terminal is arbitrary.

Then, the embodiment (1) of FIGS. 1, 2 and 3;
The pseudo data DM in (2) and (3) is the fourth
Fig. 5, Fig. 5 and Fig. 6 show one unit of pseudo data (1),
(2) and (3) are selected and connected to W pieces (W is a positive integer), and the DC unbalance (DSV) at the beginning of the leading end pseudo data of the W pieces of pseudo data is set to zero. When the DC unbalance (DSV) at the end of the last unit of pseudo data is
Conventional examples (1), (2) of FIGS. 7, 8 and 9;
(3) The DC unbalance (DSV) at each end is selected so that the value of DC unbalance cancels out.

In the above-described embodiment, digital data corresponding to the 0 level of an information signal such as an audio signal is used as one unit of pseudo data. However, other digital data may be used if it can be distinguished from original information data.

〔The invention's effect〕

According to the present invention described above, a series of digital data is subjected to dk modulation (where d and k are positive integers) and encoded, and the modulated k bits are converted to m bits (where m is a positive integer) to control the DC imbalance to be minimum by adding a margin bit, and at the end of a predetermined block of a series of modulated digital data to (k +
m) Since pseudo DC data is added to control the accumulated DC imbalance to be small, the DC imbalance of the entire recording medium does not increase regardless of the number of times of recording a series of digital data. And a method for recording digital data capable of reliably reducing both the DC unbalance of each block and the DC unbalance of the entire recording medium.

[Brief description of the drawings]

FIG. 1, FIG. 2 and FIG. 3 show an embodiment (1),
Explanatory drawing showing (2) and (3), FIG. 4, FIG. 5, and FIG.
The figures are explanatory diagrams showing examples (1), (2), and (3) of pseudo data, respectively, and FIGS. 7, 8, and 9 show conventional examples (1), (2), (3), respectively. FIG. DM is pseudo data.

Claims (2)

(57) [Claims] 1. A series of digital data is encoded by applying d-k modulation (where d and k are positive integers) and m bits (where m is a positive number) in the modulated k bits. ) To control the DC imbalance to be minimized, and to add pseudo data consisting of (k + m) bits to the end of a predetermined block of the series of modulated digital data. A method for recording digital data, characterized in that control is performed so as to reduce the cumulative DC imbalance. 2. The pseudo data added to the end of the predetermined block comprises silence data.
The method of recording digital data stored in.