WO2010054816A1

WO2010054816A1 - Recording medium, method and device for producing same, and method and device for writing and reading information

Info

Publication number: WO2010054816A1
Application number: PCT/EP2009/008068
Authority: WO
Inventors: Michael Schreiber; Gerhard Seehausen; Udo Siebertz; Guido Vermeegen
Original assignee: Frank Maiworm & Dr. Wolfhart Bosien Grundstuecks Gbr
Priority date: 2008-11-12
Filing date: 2009-11-12
Publication date: 2010-05-20
Also published as: TW201025310A; DE102008056843A1

Abstract

A recording medium (1) has a servotrack or an arrangement of servotracks which is suitable for guiding a scanning beam or a plurality of scanning beams of an information recording and/or reproduction device and, at least in sections, for forming, representing or storing main data. The servotrack or the arrangement of servotracks contains, at least in sections, a wobble signal (22) containing period regions (20) of a first signal having a period duration T₀ and half-period regions (21) of a second signal. In this case, half-period regions (21) of the second signal are inserted between the period regions (20) of the first signal.

Description

Recording medium, method and apparatus for its production, and method and apparatus for writing and

Reading information

Description

The present invention relates to a recording medium, a method and an apparatus for the production thereof, and a method and apparatus for writing (i.e., recording) and / or reading (i.e., reproducing) information to and from such a recording medium.

Important examples of such recording media include, among others, such as magnetic recording media, so-called optical recording media, for example, so-called DVDs (eg, DVD + R, DVD-R, DVD + RW or DVD-RW, etc.) which use materials whose optical reflection or transmission properties can be changed reversibly or irreversibly, for example by a laser beam of suitable wavelength and / or intensity. Such a recording medium is often referred to as an information carrier or data carrier. As far as "optical" recording media are concerned, the term "optical" as used herein should not exclude the use of electromagnetic fields or electromagnetic radiation with wavelengths outside the visible range. If in this illustration occasionally for the sake of simplicity of "a servo track" is mentioned, then it should - unless otherwise expressly stated or out of context - an arrangement of multiple servo tracks are meant. State of the art

Optical recording media often have a pre-formed servo track that may be a depression or elevation relative to the surrounding surface (the so-called "land track.") For example, a servo track preformed as a recess may be partially or wholly filled with a material whose In the preformed servo track, when writing information to the recording medium, data may be written by means of an information recording device, which is read out optically by the targeted change of the reflection or transmission behavior of this device The areas where such a targeted optical change has been made are also referred to as main data pits.

In order to maximize the storage capacity of the recording medium, there is a demand for as small a size as possible of the main data pits and the intervening areas (also referred to as "land"), to meet the accuracy requirements of the mechanical components of writing or reading In order to keep information recording and / or reproducing apparatuses within an economically justifiable framework, the servo track is usually also used to guide the scanning light beam of the information reproducing apparatus used when reading the information stored in it achieved writing data structure.

Frequently, the servo track is provided with further properties that can provide information about the linear recording speed at which the data is to be written. For example, the servo track may be deflected sinusoidally about its track center at a predetermined spatial frequency (which is also referred to as "track wobble"). For example, for a disk-shaped recording medium, the rotational speed of the motor ("disk motor") that rotates this recording medium is correct.

Some forms of such recording media are supplied with auxiliary information in the servo track containing a continuous address code for orientation on an unrecorded data carrier. Patent EP 0 325 330 describes such a recording medium in which the spatial frequency of the servo track is changed in dependence on the auxiliary information. The patents US 5,999,504 and EP 1 066 628 describe an embodiment in which the phase of the wobble signal is changed abruptly in dependence on the auxiliary information.

Since common information recording and / or reproducing apparatuses have to accept an ever-increasing number of different recording media having different recording methods, recording speeds and recording materials, different writing parameters specific to each medium are required for recording. For this reason, in certain embodiments, the auxiliary information already stored in the servo track at the time of delivery of the recording medium is extended by a control code containing the writing parameters specified for this recording medium. EP 0 397 238, for example, claims a record carrier in which the auxiliary information consisting of address code and control code is recorded in the preformed track by means of a pre-formed track modulation which includes radial sinusoidal modulation by either track wobble or track width variation.

A disadvantage of a change in the spatial frequency of the servo track turns out that the data rate of the auxiliary information that can be incorporated into the track modulation is considerably limited by the requirement of the least possible influence on the data signal to be recorded. at The methods that change the phase of the wobble signal abruptly (US Pat. No. 5,999,504 and EP 1 066 628) cause kinks in the wobble signal, which entail a significant increase in the claimed bandwidth. A disadvantage of such methods is the influencing of the main data signal to be recorded (main data pits), since a high wobble frequency results with a high auxiliary data rate, so that the upper frequency range of the modulated wobble signal overlaps with the lower frequency range of the main data signal.

Therefore, high-density optical recording media have described methods of pre-recording auxiliary information that are not based on modulation of the servo track but are performed by pre-pits disposed in or outside the servo track.

US 6,611,489 describes a recording medium having a servo track which is not tracked and which is interrupted in certain areas (also referred to as "pre-pit areas") in these areas which are not intended for data recording The pre-pits are arranged in the pre-pit area alternately on the extension of the boundary line between the servo track and the land track, so that on both sides of the servo track and land track are prefixed to have similar dimensions as the main data pits to be recorded in the land track Sides of the servo track center or the land track center pre-pits occur, precluding concurrent occurrence of the pre-pits on directly adjacent boundary lines Since synchronization of the speed of the recording medium can only occur in the pre-pit areas, which is In the case of disturbances which occur, DE 697 27 710 leads, in addition to US Pat. No. 6,611,489, a recording medium with predetermined rolling (wobble) of the servo track.

In the recording media of US Pat. No. 6,611,489 and DE 697 27 710, no data recording is possible due to the interruption of the servo track in the pre-pit areas, resulting in a loss of storage capacity. Probably for this reason, the US 6,600,711 pre-pits in the field of continuous a progressively preformed servo track, wherein the pre-pits are arranged in the middle between the land track and the adjacent servo track at predetermined intervals of equal length. These intervals correspond to the length of a recording sector of the main data pits. The pre-pits, due to their dimensions which are similar to the dimensions of the main data pits and thus have a width similar to the land or servo track, can not be arranged alternately to the center of the servo track, otherwise overlaps would result. These overlaps would lead to crosstalk problems that could significantly disrupt the evaluation of the pre-pits. For this reason, the pre-pit sequence for these products is only on the side of

Servo track located closest to the pre-pit sequence in the radial direction. Due to the permanently one-sided arrangement of the pre-pits with respect to the track center, a DC component is produced in the tracking error signal, which is responsible for a permanent error deviation of the beam guiding device of the information recording and / or reproducing apparatus used.

In addition, there is the problem that the data signal generated by the optical scanner undergoes a significant influence by the pre-pits, as these protrude considerably into the servo track and thus reduce the width of the servo track in the pre-pit areas noticeably.

Task and solution according to the invention

Object of the present invention is therefore to provide a technical teaching, with which the above-mentioned and other disadvantages of the prior art with the greatest possible compatibility with existing recording media can be avoided as much as possible.

This object is achieved by a recording medium, a method and a

Device for its production and a method and a device for writing and / or reading information on such or of a Such a recording medium according to one of the independent claims.

Preferred developments of the invention are the subject of the dependent claims.

A recording medium according to the invention comprises a servo track or array of servo tracks suitable for guiding a scanning beam or a plurality of scanning beams of an information recording and / or reproducing apparatus and at least in sections for forming, displaying or storing main data. The servo track or the arrangement of servo tracks contains, at least in sections, a wobble signal which contains period ranges of a first signal with a period duration T ₀ and half-period ranges of a second signal. In this case half-period regions of the second signal are inserted between the periods of the first signal.

This may be a substantially spiral or concentric track or an array of tracks. This track or tracks need not necessarily be usable throughout to form or display or store main data in the form of so-called master data pits. This formation, display or storage of main data is performed by a defined local change of at least one physical property of at least one material in such a track or in the tracks. Preferably, these are the reflection and / or transmission behavior of certain areas of the track or tracks.

The realization of the present invention can also be carried out by means of a device for producing a recording medium according to the invention with an optical device for recording a servo track by means of a Beam of light on a master plate. In this case, the optical device contains a modulator for generating the modulated light beam, and the modulator is controlled by a signal generator which generates a control signal corresponding to a wobble signal containing period ranges of a first signal having a period T ₀ and half period ranges of a second signal between the period ranges of the first signal half-period ranges of the second signal are inserted.

The realization of the present invention may also be accomplished by a method of manufacturing a recording medium using an optical device for recording a servo track by means of a light beam onto a master disk, and wherein the optical device includes a modulator for generating the modulated light beam and the modulator is controlled by a signal generator which generates a control signal in accordance with a wobble signal, the period ranges of a first signal having a period T ₀ and half period ranges of a second one

Contains signals, wherein between the period ranges of the first signal half-period ranges of the second signal are inserted.

The implementation of the present invention can also be carried out by means of a device for recording and / or reproducing information on or from a recording medium, with an optical device for recording main data pits in a servo track and / or for reproducing main data from this servo track, this device comprising a group of detectors from which a wobble signal is derived, the period ranges of a first signal having a period T ₀ and half period ranges of a second signal, inserted between the period ranges of the first signal half-period ranges of the second signal are.

The realization of the present invention can also be carried out by means of a method for recording and / or reproducing information on or from a recording medium, in which an optical device is used for recording main data pits in a servo track and / or for reproducing main data from this servo track, and in which a device is used, which contains a group of detectors, from which a wobble signal is derived, the period ranges of a first signal with a period T ₀ and half period ranges of a second signal, wherein between the period ranges of the first signal half-period ranges of the second signal are inserted.

Embodiments of the invention

In the following, preferred developments of the invention will be described.

A further development of the recording medium according to the invention is preferred in which half-period regions of the second signal inserted between the periods of the first signal occur at least partially in pairs. This has u. a. the advantage that these pairwise occurring half-period ranges can be arranged so that the integration of the second signal within these pairs occurring half-period ranges zero. It is meant by the expression "at least partially" that the half-period ranges - depending on the embodiment of the invention - can occur in pairs or continuously in sections only.

Further preferred is a development of the recording medium according to the invention, in which the period of the second signal is twice the predetermined period T _{0 of} the first signal. This has the advantage, inter alia, that a clock signal can be derived in a particularly simple way from a corresponding wobble signal.

Further preferred is a development of the recording medium according to the invention, in which consequences of pairwise occurring half-period of the second signal, encode the binary values ("0" or "1") of an auxiliary data signal by different sequences of the period ranges and the half-period ranges. This simplifies or facilitates, among other things, the detection of the binary values.

A further development of the recording medium according to the invention is preferred, in which the number of half-period regions of the second signal is identical in the sequence of half-period ranges for the binary value "0" of the auxiliary data signal and in the sequence of half-period ranges for the binary value "1" of the auxiliary data signal ,

A further development of the recording medium according to the invention is also preferable, in which the number of half-period regions of the second signal in the sequence of half-period regions for such a synchronization signal of the auxiliary data signal is different from the number of half-period regions in the sequence of Half-period ranges for the binary value "0" of the auxiliary data signal and in the sequence of half-period ranges for the binary value "1" of the auxiliary data signal.

A further development of the recording medium according to the invention is preferred in which the sequence of half-period ranges is at least one synchronization character of the auxiliary data signal and the sequence of half-period ranges for the binary value "0" of the auxiliary data signal and the sequence of half-period ranges for the binary value "1" of the auxiliary data signal each begins with a half-period range of the second signal.

A further development of the recording medium according to the invention is also to be preferred in which the amplitude of the second signal in the half-period regions is changed in relation to the amplitude of the first signal in the periodic ranges such that no or no noticeable sudden change occurs. A slight change in slope and / or no or no noticeable sudden change in value occurs in the wobble signal. As a result, the spectral properties of the corresponding signals are also improved in terms of easier or better detectability. An unstable or barely "noticeable" discontinuity of these signals should therefore be understood as meaning all signal profiles which contribute to the improvement of the relevant or relevant spectral properties of the corresponding signals in connection with the present invention.

In addition, a refinement of the recording medium according to the invention is preferred in which the first signal is DC-free in the period ranges and in which the paired half-period regions of the second signal are arranged such that the integration of the second signal over the half-period regions of this pair yields zero. In this context, the terms "DC-free" and "zero-result" should also be understood to mean signal characteristics in which these criteria are approximately fulfilled. It is important above all that the advantages associated with these signal properties are achieved, namely u. a. that the mean DC component of the wobble signal and thus the average error signal, which results from the guidance of the scanning beams in the middle of the servo track, can be kept permanently at zero or close to zero, and that consequently no or no significant beam following impairment due to the insertion of half a period - Odenbereichen (21) of the second signal is formed.

It is also preferable to further develop the recording medium according to the invention, which is characterized in that, with the coding length remaining constant, M can be selected by selecting any one of the auxiliary data bits and the

Synchronization sign same number N of period ranges of the first signal, which are added to the M length units of the period T ₀ , the bit length is changed so that the magnitude of the spectrum of the wobble signal falls below a previously defined threshold at least one frequency. A further development of the recording medium according to the invention is preferred in which the first signal is sinusoidal or cosinusoidal in the period ranges and the second signal is sinusoidally or cosinusoidally in the half-period ranges, the second signal being in the regions in which the first signal is sinusoidal or cosinusoidal Amounts below a predefined threshold is equal to the first signal and in the areas in which it is in magnitude above a predefined threshold, an amplitude and a period that are different from the first signal, the amplitude and the period be chosen so that no (noticeable) sudden change in slope and / or no (noticeable) sudden change in value in the wobble signal occur.

A further development of the recording medium according to the invention, in which the auxiliary data signal, which is assigned to the sequence of period ranges and half-period ranges, contains application data and / or control data and / or safety data, is preferred.

Some preferred developments of devices according to the invention for producing a recording medium according to the invention generate a wobble signal having features according to one of claims 2 to 12.

In some preferred embodiments of the method according to the invention for the production of recording media according to the invention is a

Wobblesignal with features according to one of claims 2 to 12 generates.

Some preferred refinements of the device according to the invention for recording and / or reproducing information generate a wobble signal having features according to one of claims 2 to 12.

Further preferred is a device for recording and / or reproduction of information, in which the wobble signal is sent to a decoder for decoding. the decoder for generating a rotational speed control signal for the rotary unit of the information recording and / or reproducing apparatus by producing an oscillator signal, which is derived from the wobble signal by means of a comparator circuit and an edge-triggered timing unit configured ,

Further preferred is an apparatus for recording and / or reproduction of information, in which the decoder includes a subtraction circuit for forming a difference signal, which produces the difference of the comparator output signal and the oscillator signal, with the aid of a discrete correlation in which the difference signal for the synchronization character, the auxiliary data bit = "0" and the auxiliary data bit = "1" is used to generate the synchronization character, the auxiliary data bit = "0" and the auxiliary data bit = "1".

Some preferred developments of the method according to the invention for recording and / or reproducing information use a wobble signal having features according to one of claims 2 to 12.

Further preferred is an inventive method for recording and / or reproduction of information in which the wobble signal is supplied to a decoder for decoding the auxiliary data signal, wherein the decoder for generating a rotational speed control signal for the rotary unit of the information recording and / or reproducing apparatus by making an oscillator signal derived from the wobble signal by means of a comparator circuit and an edge-triggered time measuring unit.

Further preferred is a method according to the invention for recording and / or reproducing information, in which the decoder has a subtraction circuit for forming a difference signal which represents the difference of the comparator. rator output signal and the oscillator signal includes, by means of a discrete correlation in which the difference signal for the synchronization character, the auxiliary data bit = "0" and the auxiliary data bit = "1" is based, the synchronization character, the auxiliary data bit = "0" and to generate the auxiliary data bit = "1".

Further advantages, features and applications of the present invention will become apparent from the following description taken in conjunction with the figures.

FIGS. 1a, 1b and 1c illustrate an exemplary embodiment of the wobble signal, which contains the coding of the binary auxiliary data bits (1a, 1b) and of the auxiliary data synchronization character (1c).

FIGS. 2a and 2b illustrate exemplary embodiments of smooth wobble signals with small or missing jumps in pitch.

Fig. 3 illustrates an embodiment of the information recording and / or reproducing method of the present invention using the recording medium of the present invention.

Figures 4a, 4b and 4c illustrate signals for one embodiment of a decoder (37) for the auxiliary data signal.

Figures 5a and 5b illustrate the spectrum of auxiliary data bits coded in the prior art at a bit length of 40 periods T ₀ .

Figures 6a and 6b illustrate the spectrum of auxiliary data bits coded in the prior art at a bit length of 80 periods T ₀ . Fig. 7a and 7b represent the spectrum of Hilfsdatenbits that are encoded according to an embodiment of the invention without smoothing (with pitch jump) of the wobble (22) at a bit length of 40 periods _T0.

Figures 8a and 8b illustrate the spectrum of the auxiliary data bits encoded according to an embodiment of the invention without smoothing (with pitch skip) the wobble signal (22) at a bit length of 80 periods T ₀ .

Figures 9a and 9b illustrate the spectrum of the auxiliary data bits encoded according to an embodiment of the invention with smoothing (without slope jump) of the wobble signal (22) at a bit length of 40 periods T ₀ .

Figures 10a and 10b illustrate the spectrum of the auxiliary data bits encoded according to an embodiment of the invention with smoothing (without slope jump) of the wobble signal (22) at a bit length of 80 periods T ₀ .

Fig. 11 illustrates an embodiment of the decoder (37) of the auxiliary data signal.

Fig. 12 shows an embodiment of the apparatus for producing the master plate (61) which can be used as a duplicating original of the recording medium (1) according to the present invention.

Figures 13a and 13b illustrate the difference signal (42) for the auxiliary data bit = "0" (13a) and the discrete correlation of this difference signal with itself (13b).

Figures 14a and 14b illustrate the difference signal (42) for the auxiliary data bit = "1" (14a) and the discrete correlation of this difference signal with itself (14b). Figs. 15a and 15b illustrate the difference signal (42) for the synchronization character (15a) and the discrete correlation of this difference signal with itself (15b).

Figs. 16a, 16b and 16c illustrate the discrete correlation of the difference signals for the auxiliary data bit = "0" and the auxiliary data bit = "1" (16a), the discrete correlation of the difference data for the auxiliary data bit = "0" and the synchronization character (16b) and Figs the discrete correlation of the difference signals for the auxiliary data bit = "1" and the synchronization mark (16c).

A preferred embodiment of a recording medium according to the invention has an arrangement of servo tracks which are suitable for guiding a scanning laser beam and which contain a wobble signal for coding an auxiliary signal according to one of FIGS. 1a, b, c. As a rule, this wobble signal consists of period ranges (20) of a first DC-free signal having a predetermined period T ₀ . For pre-recording of the auxiliary data signal are between the period ranges (20) of the first

Signal paired half-period regions (21) of a second signal having twice the predetermined period To has inserted. In this case, the paired half-period regions (21) are arranged such that the integration of the second signal within these pairwise occurring half-period regions (21) yields zero.

The binary values ("0" or "1") are encoded by a series of paired half-period regions (21) such that the time sequence of the half-period regions (21) for the binary value "0" is different from the time sequence of the half-period regions (21). 21) of the binary value is "1". In order to make the transition from the period ranges (20) of the first signal to the half-period range (21) of the second signal without (or without noticeable) sudden changes in slope in the wobble signal, the amplitude of the second signal against the amplitude of the first signal to be adjusted.

Due to the DC-freedom of the first signal and the property that the integration of the second signal within a pair of half-period ranges (21) is zero, the mean DC component of the wobble signal and thus the average error signal, which is in the middle of the guidance of the scanning beams the servo track is created, kept permanently at zero. As a result, there is no beam following impairment due to the insertion of half periods (21) of the second signal.

Since the wobble signal is composed exclusively of oscillations of the period T ₀ or of the period 2 To, a constant clock signal of the period T ₀ can be derived from the wobble signal. For this purpose, a control circuit with edge-controlled time measurement is preferably used, which controls the clock signal in the form of a controlled oscillator signal as a function of the zero crossings of the wobble signal. By means of this clock signal of the period T _o , whose reciprocal is related to the main data bit rate at the intended linear writing speed, a control signal can be derived, which controls the rotational speed of the recording medium.

The information recording and / or reproducing method using the recording medium (1) according to the present invention will be described with reference to FIG. The recording medium (1) has an array of servo tracks suitable for guiding a scanning laser beam and including a wobble signal (22) for encoding an auxiliary signal according to any one of Figs. 1a, b, c.

The rotary unit (32) in Fig. 3 rotates the recording medium (1) in response to a rotational speed control signal generated by the rotational speed control unit (36). In this case, the rotational speed of the recording medium (1) can be For example, it may be set so as to set a predetermined constant linear velocity or a predetermined constant angular velocity in the recording and / or reproduction of the main scanning optical beam (5) and the pilot scanning beams (6). The optical unit (30) generates the main scanning beam (5) and two pilot scanning beams (6), concentrates them on the information plane of the recording medium (1), and images the scanning beams on a group of photodetectors (34). The photodetector group consists of pilot beam detectors for the pilot scanning beams (6) and a four-divided main beam detector for the main scanning beam (5), for example. The light intensity incident on the individual detector surfaces is converted into electrical signals which are separately available for each surface element and passed on to the decoder (37) for the auxiliary data and to the decoder (38) for recorded main data pits. The decoder (37) additionally determines the speed control signal from the wobble signal (22) and sends it to the speed control unit (36). The central control unit (39), which may consist of a conventional microcomputer and / or a signal processing computer, derives from the signals of the pilot beam and main beam detectors suitable control signals for radial positioning and focusing of the optical unit (30) in a manner known per se For example, as described in "Terry W. McDaniel, Randall H. Victora: Handbook of Magneto-Optical Data Recording, Noyes Publications, Westwood, New York." The control signals are routed to the position and focus control unit (35) The intensity of the monochromatic light beam of the optical unit (30) must lie above a defined switching threshold and for information reproduction below this switching threshold for information recording corresponding intensity control ge via the light control unit (33), which is controllable by the central control unit (39).

1 shows an exemplary embodiment of the wobble signal (22), which contains the coding according to the invention of a binary auxiliary data signal. For the Auxiliary data signal comes into consideration application data, safety data and control data.

Examples of application data include prerecorded information including, for example, instructions for handling the recording medium,

• advertising information of the manufacturer,

• for entertainment or information serving image and / or sound recordings

• and the like.

As control data, for example

• addressing

• Intensity characteristics of the light source for information recording

• Characteristic values for the pulse sequences of the light source for the information recording

• Characteristics of the recording layers of the recording medium

• Characteristics for the recording speed

• Start address of the recording area

• stop address of the recording area • and the like are used.

For example, in the class of security data • Key data for authorizing the recording medium to be able to record certain program groups of a manufacturer

• Manufacturer's signature

• and the like fall.

As far as the auxiliary data signal can neither be erased nor post-recorded by the user, this information has a high safety significance. Beyond the bandwidth of the exemplary fields of application given, a large number of further possible uses are given to the person skilled in the art

The auxiliary data signal preferably consists of a sequence of binary values (auxiliary data bits) which may be associated with a binary number code. A binary number code is usually composed of the logical elements "0" and "1".

For example, if addresses consisting of four decimal places are to be coded in the wobble signal (22) according to the invention, then each decimal digit may be converted into a 4-bit binary coded decimal (BCD) binary code. Thus, each address consists of a total of 4 (decimal places) ^* 4 bits = 16 bits that can be combined to form a serial data frame. There is the additional possibility, in addition to the addresses, also coding application data, safety data and control data in the wobble signal (22). Consequently, the data frame can be extended by this information, whereby redundant bits can still be inserted into the data frame for error protection.

The data frame thus obtained is coded bit by bit serially in the wobble signal (22) according to one of FIGS. 1a, b, c. Here, for the data elements ("0", "1", 1a, b, c are delimited by the two vertical dotted lines Within this characteristic range, which is used for all data elements ("0", "1"), the respective characteristic region in the wobble signal (22) in FIGS. "Sync") has the same length, a sequence of period ranges (20) of the first DC-free signal having a predetermined period T ₀ and the preferably paired half-period ranges (21) of a second signal, which is typical for the respective data element, is established has twice the predetermined period T ₀ . The signal course within the half-period regions (21) is alternately complementary, ie a pair of half periods (21) consists of a negative signal of the second signal and a positive signal of this signal, as shown in FIGS. 1a, b, c is. As a result, the average disappears over a pair of two consecutive half-period regions (21) resulting from the integration of the second signal within this half-period pair. Due to the DC-freedom of the first signal in the period regions (20) and the second signal in a pair of half-period regions (21), the wobble signal (22) is also DC-free, so that the error-free tracking of the optical scanning beam by the position and focus control unit (35) is guaranteed.

According to FIGS. 1a and 1b, the auxiliary data bits "0" and "1" are respectively coded by two pairs of half-period regions (21) in the wobble signal (22), the sequence of period regions (20) of the first signal and of Half period ranges (21) of the second signal is different. For characterizing the beginning of the auxiliary data frame by means of a synchronization character, it is possible to use, for example, the "sync" sequence shown in Fig. 1c, which clearly differs from the sequences of the auxiliary data bits "0" and "1." Thus, the detection of the beginning of the frame For example, at the first entry into the data stream or after the intentional or erroneous skipping of data allows. Outside of the identically long identifying regions which are marked by the vertical dotted lines in FIGS. 1a, b, c, any number of period regions (20) of the first signal of the same type may be contained in the wobble signal (22).

For the spectral behavior of the wobble signal (22), the shape of the second signal in the half-period regions (21) is of crucial importance. The embodiments of a signal form shown in FIGS. 2a and 2b, in which the wobble signal 22 has no (noticeable) sudden changes in pitch and no sudden changes in value, are particularly favorable. For this purpose, the second signal can be composed within a half-period range (21) by three signal parts. In the space regions 0 <x <T ₁ and 2 T ₀ - T ₁ <x <2 T ₀ , the second signal is identical to the first signal, while the second signal is in the spatial range Ti <x <2 T ₀ -T ₁ of first signal is different. Here, the second signal has a different period and a different amplitude to the first signal.

FIGS. 2a and 2b show two exemplary embodiments in which the first signal is sinusoidal and the second signal is piecewise sinusoidal or cosinusoidal. The second signal is generated in the spatial regions 0 <x <T ₁ and 2 T ₀ - T ₁ <x <2 T ₀ with s _A (x) and in the spatial region T ₁ <x <2 T ₀ - Ti with s _B (x ), where x indicates the path on the middle line of symmetry of the servo track. Due to the requirement that no (or no significant) abrupt changes in slope, and no (or no significant) abrupt changes in values in the wobble signal (22) occur, s _A (x) (x) are the transition from the signal on the signal s _B (exactly or at least to some extent) the mathematical equations:

s _A (T _{ ) = Sin (2πT _{ / T ₀ ) = S ₈ (TO = AB COS (IK (T ₀ -T ₁ ) ZT _B )

In this case, T _{6 denote} the desired period duration and A _B the desired amplitude of SB (X). By substituting the equations, the period T ₈ results from the numerical resolution of the equation:

Tanjlπ X (T _Q - T _X ) IT ₈ ) _ Cos (2π T _x IT ₀ ) ¥ _B ^~ T ₀ Sin (2πT _x / T _Q ) ^'

For the amplitude AB, one then obtains:

T _B cos (2π T _x / T ₀ )

A _B =

T ₀ Sin (2πx {T ₀ -T _x ) IT ₈ )

For the waveform in Fig. 2a, the parameters switching threshold value were: s _A (Ti) = 0.85

Switchover points s _A (x) to s _B (x): T _{A → B} = 0, 1617 T ₀

Switchover points s _B (x) to s _A (x): T _{B → A} = 0.8383 T ₀ Period of SB (X): T _B = 2.2438 To

Amplitude of s _B (x): A ₈ = 1, 456 used.

For the waveform in Fig. 2b, the parameters switching threshold: s _A (Ti) = 0.5

Switchover points s _A (x) to s _B (x): T _{A → B} = 0.0833 T ₀

Switchover points s _B (x) to s _A (x): T _{B → A} = 0.9166 T ₀ Period of s _B (x): T _B = 2.0247 T ₀

Amplitude of s _B (x): A ₈ = 1, used 8234.

An important advantage of the waveforms according to FIGS. 2 a and 2 b compared to the signal forms known from the prior art can be seen in the fact that in this embodiment of the invention a lower signal bandwidth is claimed and less stringent demands are made in the production of a corresponding servo track the wobble generator and the quality of the impression.

In FIGS. 2a, b, only the case for the positive course of the second signal is shown by way of example. In the case of the negative curve, the switching threshold value s _A (Ti) and the amplitude A _{B are} also negative.

FIGS. 5a, b and 6a, b show the spectra of the wobble signal according to the prior art, as described, for example, in US Pat. No. 5,999,504 and EP 1 066 628. The spectrum in FIGS. 5a, b is determined for a bit length of 40 periods T ₀ , which consist of 8 periods T ₀ for encoding the respective auxiliary data bit and then 32 periods T _{0 of} the non-coded wobble signal. The spectrum in FIGS. 6 a, b is determined for a bit length of 80 periods T ₀ , which consist of 8 periods T ₀ for encoding the respective auxiliary data bit and then 72 periods T _{0 of} the non-coded wobble signal. The spacing of the five vertical grid lines in FIGS. 5a, b and 6a, b corresponds to the reciprocal of the period T ₀ . The spectral line for the reciprocal of the period T ₀ is outstanding due to the dominance of this oscillation with the frequency 1 / T ₀ .

In FIGS. 7a, b and 8a, b, the spectra of the wobbled signal (22) according to the invention are shown which, with the amplitude remaining constant, undergoes sudden changes in slope during the transition from the first to the second Signal has. The spectrum in FIGS. 7 a, b is determined for a bit length of 40 periods T ₀ (comparable to FIGS. 5 a, b), which consists of 9 periods T ₀ (= coding length) for coding the respective auxiliary data bit and subsequent 31 periods T _{0 of} the first signal exist. The spectrum in FIGS. 8 a, b is determined for a bit length of 80 periods T ₀ (comparable to FIGS. _{6 a} , b), which consists of 9 periods T ₀ (= coding length) for coding the respective auxiliary data bit and then 71 periods T _{0 of} the first signal exist.

The improvement over the prior art (FIGS. 5a, b and FIGS. 6a, b) can be seen, since in the spectra (FIGS. 7a, b and 8a, b) a faster amplitude drop occurs as a function of the frequency ,

FIGS. 9 a, b and 10 a, b show the spectra of a wobble signal (22) which has been smoothed by way of example according to the invention and which has a suitable amplitude according to the embodiments shown in FIGS. 2 a, b and thus no sudden changes in slope. The spectrum in FIGS. 9 a, b is determined for a bit length of 40 periods T ₀ (comparable to FIGS. 5 a, b), which consists of 9 periods T ₀ (= coding length) for coding the respective auxiliary data bit and subsequent 31 periods T ₀ consist of the first signal. The spectrum in FIGS. 10 a, b is determined for a bit length of 80 periods T ₀ (comparable to FIGS. _{6 a} , b), which consists of 9 periods T ₀

(= Coding length) for coding the respective Hilfsdatenbits and subsequent 71 periods T _{0 of} the first signal exist.

The improvement over the prior art (FIGS. 5a, b and FIGS. 6a, b) is clearly recognizable, since in the spectra (FIGS. 9a, b and 10a, b) a significantly faster drop in amplitude as a function of the Frequency setting.

It can be seen from the spectral investigations, with special reference to FIGS. 9a, b and 10a, b, that the decrease of the spectrum in Depending on the frequency can be increased by the bit length at the same coding length M, ie the characteristic region in the wobble signal (22), in the Fig. 1a, b, c by the two vertical dotted lines (here M = 9 T ₀ ) is increased by adding any number N of period ranges (20) of the first signal equal to the auxiliary data bits and the synchronization mark. As a result, the influence on the main data signal to be recorded (main data pits) can be further reduced since the overlap of the upper frequency range of the modulated wobble signal (22) with the lower frequency range of the main data signal becomes even smaller. In particular, it is possible to define a threshold below which the magnitude of the spectrum of the wobble signal (22) can be maintained by appropriately selecting the number N.

An exemplary embodiment of a decoder (37) for recovering the auxiliary data from the wobble signal (22) is shown in FIG. 11. With correct tracking, the line of symmetry of the photodetector group (34) is just above the middle line of symmetry of the optical image of the servo track.

In the case of correct tracking, on average, the light components of the main scanning beam (5) and the pilot scanning beam (6) are identical on both sides of the central line of symmetry of the servo track. The signals of the photodetector group (34) of the recording and / or reproducing apparatus can be linked together so that essentially the difference of the two-sided light components is processed. If the tracking of the main scanning beam (5) or the pilot scanning beams (6) is carried out with a time constant which is substantially greater than the period To, then the tracking can not follow the track wobble. The difference-linking of the signals of the photodetector group (34) produces the wobble signal (22).

The wobble signal (22) is supplied to the comparator circuit (50), the logic value "1" and the signal values above a running threshold below this threshold the logic value "0." In order to eliminate DC voltage fluctuations, which occur due to unavoidable tolerances of the recording medium and can influence the position of the zero crossings of the wobble signal (22), the comparator threshold is adjusted by means of the low-pass circuit (53). The signal (40) adjusts itself at the output of the comparator circuit, as shown in FIG. 4 for the synchronization symbol "Sync" (FIG. 4c), for the auxiliary data bit = "O" (FIG. 4a) and for the auxiliary data bit = "1" (Fig. 4b) is shown.

The signal (40) and the binary signal (41) generated by the voltage controlled oscillator (58) are applied to the inputs of the edge-triggered

Time measuring unit (51). The task of the time measuring unit (51) is to switch to the logical value "1" at each positive edge of the signal (40), ie at the transition from the logical value "0" of the signal (40), and at every negative edge, ie at Transition from the logical value "1" of the signal (40) to the logical value "0" to determine the time between the respective edge of the signal (40) and the nearest positive edge of the binary oscillator signal (41). If the relevant edge of the signal (40) lies ahead of the associated positive edge of the signal (41), the determined time difference is output as a negative control voltage value proportional thereto at the output of the time measuring unit (51). In the event that the edge of the signal (40) is behind the associated positive edge of the signal (41), the determined time difference is output as a positive control voltage value proportional thereto. With the aid of the control voltage, which must be filtered for stability reasons with the aid of the low-pass filter (52), the frequency or the period duration of the signal (40) is regulated in such a way that it is as accurate as possible with the period T _{0 of} the first signal that occurs in the period ranges (20) matches.

Since the signal (40) usually has the period T ₀ and the period duration 2 T ₀ only in the less frequently occurring half-period ranges (21), the time constant of the low-pass filter (52) can be chosen such that it is on the order of ten times the period T ₀ . Thus, the change of the period in the signal (40) during the half-period ranges (21) has no influence on the stability of the oscillator signal (41), from which with the aid of the speed control unit (36) the control signal for the rotary unit (32) of the recording medium (1) can be derived.

With the aid of the subtraction circuit (54), which can be realized by a logical exclusive-OR circuit, the difference of the signal (40) and the oscillator signal (41) is formed. The difference signal (42) available at the output of the subtraction circuit (54) has for each component of the auxiliary data signal "Sync" (Figure 4c), auxiliary data bit = "0" (Figure 4a) and auxiliary data bit = "1 "(Fig. 4b) a clearly distinguishable waveform.

To detect the signal waveform for the sync symbol "Sync", the circuit (55) is used, which performs the discrete correlation between the binary in the circuit (55) stored binary waveform for the sync and the course of the binary difference signal (42) With sufficient agreement, an indication signal is generated at the output of the circuit (55).

To detect the waveform for the auxiliary data bit = "0", the circuit

(56), which determines the discrete correlation between the binary desired waveform for the auxiliary data bit = "0" stored in the circuit (56) and the

Course of the binary difference signal (42) performs. With sufficient agreement, an indication signal is generated at the output of the circuit (56).

To detect the waveform for the auxiliary data bit = "1", the circuit

(57), which determines the discrete correlation between the desired binary signal waveform stored in the circuit (57) for the auxiliary data bit = "1" and the

Course of the binary difference signal (42) performs. With sufficient agreement, an indication signal is generated at the output of the circuit (57). The discrete correlation procedure will be explained with reference to Figs. 13a, b, 14a, b, 15a, b and Figs. 16a, b, c. The difference signal (42), which is for the auxiliary data bit = "0" in FIG. 13a, for the auxiliary data bit = "1" is shown in FIG. 14b and for the synchronization character is shown in FIG. 15a, is discretized so that equidistant intervals samples are taken out of this signal in the form of a sequence of numbers. By means of this process, the discrete difference _signal s _Dιff (n T ₀ / N _d ) is formed from the continuous difference _signal s _Dlff (x), where N _{d is} the number of samples related to the period range (20) of the first signal. The discrete correlation S _KO rn _{, 2} (k T ₀ / N _d ) of two different discrete difference _signals s _Dιff i (n T ₀ / N _d ) and s _Oιff2 (n T ₀ / N _d ) is then defined by the relationship:

Sκ _orri2 (k -T ₀ / T _d ) = Σ s _Dιffι ((n) .T ₀ / T _d ) - s _Dιff2 ((n - k) -T ₀ / T _d ) n

Accordingly, the discrete correlation S _Kθ rri (k T ₀ / N _d ) of the discrete difference _signal s _Dιff i (n T ₀ / N _d ) with itself is defined by the relationship:

S _Korrl (k -T ₀ / T _d ) = Σ s _Dιffl ((n) -T ₀ / T _d ) - s _Dιffι ((n - k) -T ₀ / T _d ) n

Since the difference signal (42) assumes only binary values, the multiplication in the execution of the discrete correlation can be simplified by a logical AND operation.

13b shows the course of the discrete correlation of the difference signal with itself for the auxiliary data bit = "0", in FIG. 14b the course of the discrete correlation of the difference signal with itself for the auxiliary data bit = "1" and in FIG. 15b shows the course of the discrete correlation of the difference signal with itself for the synchronization character. Essential for the decision as to which auxiliary data bit or whether the synchronization character is present is the value of the discrete correlation at zero point, the zero point being determined by the first Edge of the difference signal (42) is indexed as a reference. The following values of the discrete correlation at the zero point can be seen from FIGS. 13b, 14b and 15b:

Auxiliary data bit = "0" Auxiliary data bit = "1" Synchronization character

Fig. 13b Fig. 14b Fig. 15b

Sκorr _θ (O) = 2.4 Sκorri (O) = 2.4 SκorrSync (O) ⁼ 3.2

For unambiguous detectability, the requirement is that the values of the discrete correlation of the respective difference signal with itself at the zero point be significantly greater than the values of the discrete correlation of different difference signals. FIG. 16a shows the profile of the discrete correlation of the difference signal for the auxiliary data bit = "0" with the difference signal for the auxiliary data bit = "1", FIG. 16b shows the course of the discrete correlation of the difference signal for the auxiliary data bit = "O" with the difference signal for the synchronization character and in Fig. 16c, the course of the discrete correlation of the difference signal for the auxiliary data bit = "1" is shown with the difference signal for the synchronization character. The following values of the discrete correlation at the zero point can be seen from FIGS. 16a, 16b and 16c:

Auxiliary data bit = "0" Auxiliary data bit = "0" Auxiliary data bit = "1" Auxiliary data bit = "1" Synchronization character Synchronization character

Fig. 16a Fig. 16b Fig. 16b

SκorrO.i (O) = 0.8 S _K orr0, Sync (0) = 0.8 S _K orr1, Sync (0) = 0.8

It can be seen that the value of the discrete correlation of the respective difference signal (for the auxiliary data bit = "0", for the auxiliary data bit = "1" and for the synchronization character) with itself in the zero point is significantly greater than 2, while the values the discrete correlation of different differential signals at zero point are significantly less than 1. Therefore, the method of discrete correlation in the circuit (55), in the circuit (56) and in the circuit (57) for the unique detectability for the auxiliary data bit = "O", for the auxiliary data bit = "1" and for the synchronization character.

This unambiguous detectability is still present even if the difference signal (42) is influenced by possibly occurring errors in the wobble signal (22). In this case too, where a shift of the zero point by one or more steps T ₀ / N _d to the left or to the right would result in the diagrams of the discrete correlation, the values of the discrete correlation of the discrete correlation are in a sufficiently wide range each difference signal with itself is significantly greater than the values of the discrete correlation of different differential signals.

FIG. 12 shows an exemplary embodiment of the generating device for producing the servo track with period regions (20) of the first signal and half-cycle regions (21) of the second signal on a master plate (61). The monochromatic light source (68), which may be a laser, produces a light beam (69) having a wavelength approximately equal to the width of the servo track. With the aid of the electro-optical modulator (66), the radial position of the light beam (69) in response to the control voltage generated by the signal generator (67) to the symmetry line of the light beam (69) alternately to the pivot point of the master plate (61) or moved away from the pivot point of the master plate (61).

The profile of the control voltage at the output of the signal generator (67) corresponds to the course of the wobble signal (22) which is encoded as a function of the auxiliary data signal by the inventive sequence of half-period regions (21) of the second signal between the periodic regions (20) of the first signal , The modulated by the modulator (66) light beam (70) is focused by means of the movable focus lens (64), which is controlled by the position and focus control unit (65) to the light spot (60). With the aid of this light spot (60), the photoresist, with which the surface of the master plate (61) is coated, exposed to generate the required geometry of the servo track.

The thickness of the photoresist should correspond to the depth of the servo track to be generated. The required beam geometry is generated by means of the movable focus lens (64) in such a way that the light spot (60) on the surface of the master plate (61) is approximately matched to the width of the servo track. During the exposure process, the focus lens (64) and the master plate (61) are moved by means of the rotary unit (62) parallel to the focal plane of the light spot (60), so that a servo track having a spiral or concentric circular structure, or sets an array of servo tracks. In order to take into account possible unevenness of the master plate, the movable focus lens (64) is always readjusted by means of the positioning and focus control unit (65) in order to achieve a constant light spot. In a subsequent etching process, the exposed areas of the photoresist are eliminated Finally, the master plate (61) is coated with a reflective layer.

From the master plate (61), large quantities of plastic impressions, which are provided with one or more recording layers, can be produced in combined electroplating and injection molding processes. However, such techniques for the production of plastic data carriers with a servo track are known to the person skilled in the art and are not the subject matter of the present description.

Although the invention has been described with reference to embodiments, the invention is not limited to these embodiments.

»Te of the reference numbers

1. 1, Fig. 2: riodebereiche (20) of the first signal lbperiodenbereiche (21) of the second signal) bblesignal (22)

1. 3: marking medium (1) uptabtaststrahl (5)

Dt scanning jets (6) table unit (30)

Unit (32) for the recording medium (1) ht control unit (33) otodetectors (34) sitions- and Fokussteuereinheit (35) number control unit (36) coder (37) for the Hilfdatensigπer coder (38) for recorded main data pits ( 23) ntral control unit (39)

J. 4, Fig.11: jnal (40) after comparator circuit (50)

■ cillator signal (41) reference signal (42) mparator circuit (50) with tracking comparator threshold mken-controlled time measuring unit (51) ifpass (52) sfpass (53) ibtraktionsschaltung (54) nc detection (55) fsdatenbit = "O" detection (56 fsdatenbit = "1" detection (57) voltage controlled oscillator (58) g. 12: heat stain (60)

3-plate (61) for master plate (61) Number control unit (63) Focusable lens (64)

) sition and Focus Control Unit (65) Electro-Optical Modulator (66) Signal Generator (67) Onochromatic Light Source (68)

Direct beam (69) modulated light beam (70)

Claims

- 33 patent claims

A recording medium (1) having a servo track or an array of servo tracks suitable for guiding a scanning beam or a plurality of scanning beams of an information recording and / or reproducing apparatus and at least in sections for forming, displaying or storing main data this servo track or this arrangement of servo tracks at least partially contains a wobble signal (22), characterized in that the wobble signal (22) period ranges (20) of a first signal having a period T ₀ and half period ranges (21) of a second

Contains signals, between the period ranges (20) of the first signal half-period ranges (21) of the second signal are inserted.

2. Recording medium (1) according to claim 1, in which between the period ranges (20) of the first signal inserted half-period regions (21) of the second signal occur at least partially in pairs.

3. Recording medium according to one of the preceding claims, wherein the period of the second signal is twice the predetermined period T _{0 of} the first signal.

A recording medium according to any one of the preceding claims, wherein sequences of paired half-period regions (21) of the second signal represent the binary values ("0" or "1") of an auxiliary data signal through different sequences of the periodic regions (20) and half-period regions (21). encode.

5. Recording medium according to one of the preceding claims, wherein the number of half-period regions (21) of the second signal in the - 34 -

Sequence of half-period regions (21) for the binary value "0" of the auxiliary data signal and identical in the sequence of half-period regions (21) for the binary value "1" of the auxiliary data signal.

A recording medium according to any one of the preceding claims, wherein said auxiliary signal may include at least one synchronization mark and wherein the number of half-period regions (21) of the second signal in the sequence of half-period regions (21) for such a synchronization character of the auxiliary data signal is different from the number of times Half-period regions (21) in the sequence of half-period ranges (21) for the binary value "0" of the auxiliary data signal and in

A sequence of half-period regions (21) for the binary value "1" of the auxiliary data signal.

7. A recording medium according to one of the preceding claims, wherein the sequence of half-period regions (21) for at least one synchronization character of the auxiliary data signal and the sequence of half-period regions (21) for the binary value "0" of the auxiliary data signal and the sequence of half-period regions (21 ) starts for the binary value "1" of the auxiliary data signal in each case with a half-period range (21) of the second signal.

A recording medium according to any one of the preceding claims, wherein the amplitude of the second signal in the half-period regions (21) is changed from the amplitude of the first signal in the period regions (20) such that no or no noticeable sudden change in slope and / or no or no noticeable sudden change in value occurs in the wobble signal (22).

9. Recording medium according to one of the preceding claims, wherein in the period ranges (20), the first signal DC-free And in which the paired half-period regions (21) of the second signal are arranged so that the integration of the second signal over the half-period regions (21) of this pair yields zero.

10. Recording medium according to one of the preceding claims, characterized in that at the same coding length

M is changed by selecting an arbitrary number N of period ranges (20) of the first signal, which are added to the M length units of the period T ₀ , for the auxiliary data bits and the synchronization character, such that the magnitude of the spectrum of the wobble signal ( 22) falls below a previously defined threshold at least one frequency.

1 recording medium according to any one of the preceding claims, characterized in that in the period regions (20), the first signal sinusoidal or cosinusoidal and in the half-period regions (21), the second signal piecewise sinusoidal or cosinusoidal, wherein the second signal in the Areas where it is below a predefined threshold, is equal to the first signal, and in the areas where it is in magnitude above a predefined threshold, has an amplitude and a period different from the first signal, wherein the amplitude and the period are selected so that no sudden change in slope and no sudden change in value in the wobble signal (22) occur.

A recording medium according to any one of the preceding claims, wherein the auxiliary data signal associated with the succession of period ranges (20) and half period ranges (21) includes application data and / or control data and / or security data. - 36 -

13. A device for producing a recording medium (1), in particular according to at least one of claims 2 to 12, with a device for recording a servo track by means of a write beam (69) on a master plate (61), characterized in that the optical device is a modulator (66) for generating the modulated light beam (70) and the modulator (66) is controlled by a signal generator (67) which generates a control signal corresponding to a wobble signal (22), the period ranges (20) of a first signal having a period To and half-period regions (21) of a second signal, wherein between the period regions (20) of the first signal

Half period regions (21) of the second signal are inserted.

14. Manufacturing apparatus according to claim 13, wherein a wobble signal with features according to one of claims 2 to 12 is generated.

15. A method for producing a recording medium (1), in particular according to at least one of claims 1 to 11, in which a device for recording a servo track by means of a writing beam (69) on a master plate (61) is used, characterized in that the optical device contains a modulator (66) for generating the modulated light beam (70) and the modulator (66) is controlled by a signal generator (67) which generates a control signal corresponding to a wobble signal (22) comprising period ranges (20) of a first signal having a period T ₀ and half period ranges (21) of a second signal, wherein between the period ranges (20) of the first signal half-period ranges (21) of the second signal are inserted.

16. A manufacturing method according to claim 15, wherein a wobble signal is generated with features according to one of claims 2 to 12. - 37 -

17. An apparatus for recording and / or reproduction of information on or from a recording medium (1), in particular according to one of claims 1 to 1 1, with an optical device for recording main data pits in a servo track and / or Returning main data from this servo track, characterized in that this device comprises a group of detectors (34) from which a wobble signal (22) is derived, the period ranges (20) of a first signal having a period T ₀ and half period ranges ( 21) of a second signal, half-period regions (21) of the second signal being interposed between the period regions (20) of the first signal.

18. A device for recording and / or reproducing information according to claim 17, wherein the wobble signal (22) has features according to one of claims 2 to 12.

19. An information recording and / or reproducing apparatus according to any one of claims 17 or 18, wherein the wobble signal (22) is supplied to a decoder (37) for decoding the auxiliary data signal, the decoder (37) for generating a speed signal. Control signal for the rotary unit (32) of the information recording and / or reproducing apparatus by producing an oscillator signal (41) derived from the wobble signal (22) by means of a comparator circuit (50) and an edge-triggered time measuring unit (51).

20. An information recording and / or reproducing apparatus according to claim 19, wherein said decoder (37) comprises a subtraction circuit

(54) for forming a difference signal (42), which produces the difference between the comparator output signal (40) and the oscillator signal (41), in order to use a discrete correlation in which the difference - 38 -

signal (42) for the synchronization character, the auxiliary data bit = "0" and the auxiliary data bit = "1" is used to generate the synchronization character, the auxiliary data bit = "0" and the auxiliary data bit = "1".

21. A method for recording and / or reproduction of information on or from a recording medium (1), in particular according to one of claims 1 to 11, in which an optical device for recording main data pits in a servo track and / or Playback of main data is used by this servo track, characterized in that a device is used, which contains a group of detectors (34), from which a sweep signal (22) is derived, the period ranges (20) of a first signal having a period T ₀ and half-period ranges (21) of a second signal, wherein between the period ranges (20) of the first signal half-period ranges (21) of the second signal are inserted.

22. A method for recording and / or reproduction of information with a sweep signal having features according to one of claims 2 to 12.

23. A method for recording and / or reproducing information according to claim 21 or 22, wherein the sweep signal (22) is fed to a decoder (37) for decoding the auxiliary data signal, the decoder (37) being used to generate a speed signal. Control unit for the rotary unit (32) of the information recording and / or reproducing apparatus by producing an oscillator signal (41) derived from the wobble signal (22) by means of a comparator circuit (50) and an edge-triggered time measuring unit (51) is.

A method of recording and / or reproducing information according to claim 23, wherein said decoder (37) comprises a subtraction circuit - 39 -

(54) for generating a difference signal (42), which produces the difference of the comparator output signal (40) and the oscillator signal (41), contains, with the aid of a discrete correlation, in which the difference signal (42) for the synchronization character, the auxiliary data bit = "0" and the auxiliary data bit = "1" is used to generate the synchronization character, the auxiliary data bit = "0" and the auxiliary data bit = "1".