Abstract: In order to help maximize the capacity of an optical storage device, and increase the efficiency of addressing, a unique addressing scheme is utilized to provide addressing for an optical storage disk. Importantly, this scheme is compatible with multilayer disks and helps to minimize the potential for errors. In the addressing scheme of the present invention, the storage media is provided with a wobbled groove, which includes addressing information for the media. More specifically, the surface of the media is divided into predetermined sections, or portions, each portion having a selected number of wobble periods. Within these wobble periods, the amplitude of one single wobble period is either reduced or eliminated. The location of this reduced or eliminated wobble signal can then be determined by the readout system of the present invention and utilized to provide addressing information.

Abstract: For the purpose of providing sector-address information on optical disks, a robust header is realized by utilizing a very simple encoding method that allows asynchronous reading. In order to provide robustness and reliability, the header uses a biphase data format to encode addressing information. The embossed header is further configured with redundant address-fields in a checkerboard pattern between adjacent tracks, in order to provide robustness for media-contamination. Each address-field starts with a unique address-mark and ends with parity-check information to provide reliable error-detection. The entire header can be decoded without the need for a slice-level, thus making it very tolerant to amplitude-variations and DC-offset variations. By combining these characteristics, a header is achieved which is reliable and inherently resistant to failures in providing sector-address information on optical disks.

Abstract: In order to provide a low noise laser beam, a noise reducing feedback network is provided which creates a noise reducing signal and provides that signal to the laser itself. In order to produce the noise reducing signal, the operation of the laser is monitored and the feedback signal is a direct result of this monitoring. Monitoring is accomplished by a fast-forward sense detector, which receives a portion of the laser beam from the operating laser. The output from this fast-forward sense detector is provided to an amplifier which inverts and amplifies the signal. A noise reduction feedback network then receives the amplified signal, appropriately filters this signal, and provides it to the laser itself so as to reduce noise in the laser-beam for the frequency band of importance for reading the recorded data from the optical medium.

Abstract: A system and method for use in a data storage system which provides a combined phase lock loop (PLL) that utilizes a common Voltage Controlled Oscillator (VCO) and common integrator/loop-filter, but which is operational in a wobble-mode and a data-mode to provide most optimum operation and quick capture. Digital circuitry is primarily used in addition to the VCO and a loop-filter for acquiring frequency and phase lock while the optical disc drive is writing and reading. A digital Phase-detector for operation in the wobble-mode employs a down-counter that can be configured for both Frequency-Lock and Phase-Lock in a way that offers a large capture range and can adapt quickly to the multiple data-zones of the media-format.

Abstract: In order to minimize potential damage to a rewritable storage media, and to consequently extend the life of the media, the laser power is carefully controlled in order to avoide sharp power transitions. Rather than simply turning the laser power on to its full power level, the power utilized during writing dedicated sections of data sectors is transitioned from 0 to its full power level over a desired period of time. In this way, the thermal shock caused by repeated rewriting in these areas can be minimized, thus extending the life of the rewritable media.

Abstract: The accuracy of a data storage device is improved by incorporating a number of multipurpose reference bytes throughout the data. The reference bytes are used to coordinate the timing and accuracy of data when retrieved from the media. Additionally, the referene bytes provide meaningful error correction information in a manner that is easily implemented. This use of reference bytes supplements many well known error correction methodologies to provide for the accurate retrieval of information to the user. In order to coordinate the use of reference bytes, unique operations are undertaken using a predefined preamble to appropriately set the operating parameters of the storage device. For example, both the preamble and the reference bytes are used to carefully control the most optimun gain and phase control for the data storage device.

Abstract: Writing predetermined data pattern to an allocated segment of a disk drive and appropriately reading that one data pattern while varying the read focus characteristics provides for efficient and effective read focus optimization in an optical disk drive. In order to produce helpful data, the read focus offset is varied while reading the different segments of the data pattern, thus producing read out signals with different peak to peak amplitudes. This is compared to data which is obtained by reading the same data pattern while the offset is held constant. Optimization of the read focus offset is carried out and made possible by appropriate analysis of the waveforms produced when reading the predetermined data pattern in these two reading passes. By appropriately tracking the results of the various read focus offsets, an optimum read focus offset can be easily determined.

Abstract: In order to provide a low noise laser beam, a noise reducing feedback network is provided which creates a noise reducing signal and provides that signal to the laser itself. In order to produce the noise reducing signal, the operation of the laser is monitored and the feedback signal is a direct result of this monitoring. Monitoring is accomplished by a fast-forward sense detector, which receives a portion of the laser beam from the operating laser. The output from this fast-forward sense detector is provided to an amplifier which inverts and amplifies the signal. A noise reduction feedback network then receives the amplified signal, appropriately filters this signal, and provides it to the laser itself so as to reduce noise in the laser-beam for the frequency band of importance for reading the recorded data from the optical medium.

Abstract: A method, circuit and system for selectively and adaptively effecting conditioning of selected samples of a read signal in storage technologies. A circuit embodying the present invention includes sample logic, arithmetic logic and conditioning logic. The sample logic receives samples and provides a main sample and one or more selected neighbor samples. The arithmetic logic compares the main sample to the neighbor samples toward determining satisfaction of selected conditioning criteria. If the selected conditioning criteria are satisfied, the conditioning logic selectively and adaptively effects level conditioning as to the main sample. Further, the level conditioning is combined with a rule compliance system to insure the read data is following the protocol of the data coding format being used.

Abstract: A method, circuit and system for selectively and adaptively effecting conditioning of selected samples of a read signal in storage technologies. A circuit embodying the present invention includes sample logic, arithmetic logic and conditioning logic. The sample logic receives samples and provides a main sample and one or more selected neighbor samples. The arithmetic logic compares the main sample to the neighbor samples toward determining satisfaction of selected conditioning criteria. If the selected conditioning criteria are satisfied, the conditioning logic selectively and adaptively effects level conditioning as to the main sample. Further, the level conditioning is combined with a rule compliance system to insure the read data is following the protocol of the data coding format being used.

Abstract: An optical recording medium having a number of adjacent tracks for storing digital optical information is provided, such as an optical disc. The tracks extend in a tangential direction, for example, surrounding the center of the disc. Each track is separated by a pitch amount in a radial direction, for example, outward from the center across the tracks. The tracks each have a servo field comprising one tracking mark located on the track in one of four discrete tangential positions A, B, C and D on the track. There is a mark in one of these four positions for every four adjacent tracks on the media. The position of the tracking marks repeat in the same sequence for every four adjacent tracks. For any four such adjacent tracks, the tracks having marks at positions A and B are separated by one track, and tracks having marks at positions C and D are separated by one track.

Abstract: A method, circuit and system for selectively and adaptively effecting conditioning of selected samples of a read signal in storage technologies. A circuit embodying the present invention includes sample logic, arithmetic logic and conditioning logic. The sample logic receives samples and provides a main sample and one or more selected neighbor samples. The arithmetic logic compares the main sample to the neighbor samples toward determining satisfaction of selected conditioning criteria. If the selected conditioning criteria are satisfied, the conditioning logic selectively and adaptively effects level conditioning as to the main sample. Further, the level conditioning is combined with a rule compliance system to insure the read data is following the protocol of the data coding format being used.

Abstract: A method and apparatus for recovering data from an optical read channel provides for improved recording density by tolerating lower phase and amplitude margins. The method includes digitizing a plurality of samples of a first signal, clipping the digitized samples of the first signal, digitally differentiating the clipped digitized samples, determining the relative locations of signal polarity changes, and generating logical values for channel bits based, at least in part, on the relative locations of signal polarity changes. The apparatus for recovering data from an optical read channel includes a signal-level limiter, a digital differentiator coupled to the signal-level limiter, a min/max detector coupled to the digital differentiator, a zero-crossing detector coupled to the digital differentiator, an update signal generator coupled to the zero-crossing detector and the min/max detector, and a channel bit transition generator.

Abstract: During recording or reading of data in an optical record carrier such as a disc, focus is optimized by adding a focus offset signal to the focus servo error signal. Each frame contains pre-formatted control marks in a servo field, and reference data marks recorded there at a time of data recording. The focus offset signal is optimized by spacing the reference data marks a distance as close as any data marks between which a zero or non-recorded position must be resolved, and taking samples of the optical readout signal as the optical scanning beam passes over or adjacent the reference marks. Four samples are used, taken between the peaks of the signal corresponding to the two reference data marks.

Abstract: The beginning of a segment within a track of a record carrier, having a plurality of frames in each segment, is identified by detecting the presence of a control mark at a given position near the beginning of a frame, and the absence of a control mark at an adjoining position at which a control mark will be found in all other frames of the segment. The other frames of each segment are free from a mark at the given position. The next bit position containing a mark, after the given position and its adjoining position, is the clock bit position used for bit clock synchronization. An apparatus for reading these marks may include a qualification circuit for evaluating the magnitude of the difference in detector output at the given bit position and the adjoining bit position.

Abstract: The present invention provides a track format for an optical record carrier that is useful in producing a tracking signal with a substantially constant slope at its zero-crossing point for a range of track pitches. The preferred embodiment of track format is also useful in producing a tracking signal that has a substantially constant amplitude over a range of track pitches. The track format, in the preferred embodiment, employs wobbled pits. The sequence in which the wobbled pits occur alternates between adjacent tracks and the offset of the wobbled pits with respect to the center line of a track remain constant regardless of the track pitch. The preferred embodiment of the track format also includes a reference pit that is used to establish the threshold detection level for the read electronics. The location of the reference alternates between tracks to reduce the effect of radial interference on the signal produced using the reference pit and thereby allow an optimal threshold level to be established.

Abstract: The present invention provide an apparatus and method for verifying that a record carrier has been transformed from a first state to a second state in accordance with the state of a binary information signal being recorded thereon. In operation, the apparatus detects the signal generated by the record carrier during the supposed transformation and compares this signal to the corresponding portion of the binary information signal to determine whether or not the transformation has taken place, i.e., verifies the transformation. The present invention, in one embodiment, is employed in an optical disk system.

Abstract: Encoding and decoding of track address information stored on an optical disk is provided. The optical disk includes a number of tracks, each track being definable as having a plurality of position segments for storing track address information. Each of the position segments includes a single recording mark. The location of the recording mark in the position segment is indicative of the value of a digit that represents the encoded track address information. Preferably, the location of only one recording mark for a position segment changes between adjacent disk tracks. When decoding the track address information read from the optical disk, differential detection is utilized.

Abstract: An optical disk recording system including a record medium is disclosed for providing an accurate track crossing count and an accurate track following signal. A first embodiment utilizes off-centered wobbled areas located in the headers of the record medium. The high frequency content of a first signal is combined with the low frequency content of a second signal, which is generated using the wobbled areas. In another embodiment, light-reflective discontinuities are provided in the header areas of the record medium. A qualifier and an AGC are utilized in providing a corrected track following signal. In still another embodiment, reflective discontinuities are located in the servo areas of the record medium. In such an embodiment, it is preferred that there be a fixed gain adjustment to a radial push-pull signal.

Abstract: An optical information recording and/or read system comprises an optically readable record carrier (1) and an optical read and/or recording apparatus (FIG. 2). The record carrier (1) is provided with substantially concentric tracks (2). The record carrier (1) is divided into sectors (4). In the tracks of each sector address information is recorded by means of prior recorded radially juxtaposed address information patterns (8). The read and/or recording apparatus (FIG. 2) comprises a driver (20, 21) for rotating the record carrier (1), scanner (23, 25) for scanning the tracks (3) with a radiation beam (2) for the purpose of recording and/or reading, a closed-loop tracking system (23, 26) for keeping the radiation beam (24) aimed at the track (6) to be scanned, and an angular-position-detection system (23, 26, 27) for determining the angular position of the record carrier (1).