JPS6148132A - Storage method of optical digital data - Google Patents

Abstract

PURPOSE:To extract a read signal with less level fluctuation even with a low resolution read sensor such as a CCD image sensor by arranging a pit to the change point of a data modulation waveform to be recorded to apply optical digital data recording. CONSTITUTION:A recording pit is provided to a change point from H to L of an FM modulation waveform of a data or from L to H. Then each recording pit is narrow in the scanning direction and thin and long in a direction orthogonal to the scanning direction, so-called a rectangular form and all pits have the same size and shape. Further, the pit interval is from the data switching pint to another switching point, and in case of the figure, in selecting the pit interval to a data (1) as (1), the pit interval to a data (0) is ''1'' or ''2'', and the interval is not longer nor shorter than the interval. Thus, in a waveform (g) detecting a pit by the CCD, the notched part corresponds to the pit (signal) and the remaining part corresponds to the pit interval (inter-signal space).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a recording method of optical digital data, and particularly to a recording method suitable for reading with a relatively low resolution reading sensor such as a COD image sensor.

(Background technology and its problems) For example, in order to record digital data as shown in FIG. 2(a), appropriate modulation is first applied.
FM modulation is applied instead of as shown in b). Next, this F
Data pits are formed on an optical recording medium according to the M modulation waveform. 'As shown in FIG. 2(C), this data pit adopts a method in which a pit is present at the H level of the modulation waveform, or vice versa, and information is given to the length of the pit.

However, in this recording method that gives information to the pit length, the waveform read by the COD image sensor is the second waveform.
The result is as shown in Figure (d), and the laser reading shown in Figure 2 (e).
The reproducibility of the captured waveform cannot be achieved by IJ. This is COD
This is due to the low resolution of . Therefore, in order to perform reading with a COD image sensor, it is necessary to change the recording method.

[Purpose of the invention]

The present invention has been made in consideration of the above points, and an object of the present invention is to provide an optical digital data recording method suitable for reading with a low-resolution reading sensor such as a COD image sensor.

[Summary of the invention]

In order to achieve this objective, the present invention provides an optical digital data recording method in which digital data to be recorded is modulated, pits are arranged at changing points of the signal waveform after modulation, and information is attached to the pit positions. I will provide a.

[Embodiment] The present invention will be explained below by way of an embodiment with reference to FIG.

Figures 1 (a) and (b) show the same data J3 and FM modulation waveforms as in Figures 2 (a) and (b), and Figure 1 (f
) is the recording pit according to the present invention, and (g) is the recording pit according to the present invention.
This shows a waveform read by OD.

Recording pits 1 to 1 according to the present invention are shown in FIGS. 1(f) and 1(b).
), it is installed at the point where the FM modulation waveform of the data changes from 11 to 11 or from L to H. Each recording pit is narrow in the scanning direction and has 111 holes in the direction perpendicular to the scanning direction, and is so-called rectangular, and all have the same size and shape. Also, the distance between IC pits is from the data switching point to the switching point;
Then, the distance between the pins 1 and 3 for the data ``Oj'' is 1 or 2, and it cannot be longer or shorter than this.

Therefore, the waveform when pits are detected by COD is as shown in FIG. 1 (Q).

Comparing this waveform with the read waveform of COD in J3 using the recording method that gives information to the pit length in Fig. 2(d),
There is a noticeable difference in the overall level variation of the read waveform.

This is due to the following reason. The COD is an element that handles charge, and the longer the signal applied, the higher the level of the read waveform, and the longer the space between signals, the lower the level of the read waveform. As a result, the length of the signal and the length of the space between signals The level of the read waveform varies significantly depending on the combination of the variations. In contrast to the conventional recording method, in the present invention, the length of the pit (signal) is constant, and only the distance between pits (space between signals) is a predetermined length and the two.
If only the change in double length is indicated, the range of change in the magnitude of the charge handled by the COD will be small.

In the waveform shown in FIG. 1 (9), the notched portion corresponds to the pit (signal \'3), and the remaining portion corresponds to the inter-pit portion (inter-signal space). The length of the pit in the scanning direction is CO
It should be determined according to the resolution of D, and must be set so that the waveform is sufficiently cut. Then, it is only necessary that the recording pit is located precisely at the changing point of the data modulation waveform.

If such conditions regarding the recording pits are observed, the recorded data can be accurately reproduced by detecting the level of the COD read waveform.

[Modified example]

In the above embodiment, the FM modulation waveform of the data to be recorded is recorded, but there are various modulation methods, and the present invention can be applied to modulation waveforms other than FM modulation.

(Effects of the Invention) As described above, the present invention records optical digital data by arranging pits at changing points of the modulation waveform of data to be recorded. A high-resolution reading sensor can also provide a reading signal with little level fluctuation. As a result, there is an advantage that the circuit that handles the output signal of the reading sensor may have a simple configuration.

[Brief explanation of drawings]

Fig. 1 (a), (b), (f), (()) are time charts for reducing optical digital recording data and its read waveform according to the present invention, Fig. 2 (a) to (e) are This is a time chart showing optical digital data and its read waveform according to the conventional recording method in which information is given to the length of the pit. Applicant's agent: Inomata Kiyote December Nokoday

Claims (1)

[Claims] 1. A method of recording optical digital data after modulating digital data to be recorded, characterized in that pits are arranged at changing points of the signal waveform after the modulation.