Abstract: The present invention provides for an apparatus and method of controlling writing a signal to an optical disc in an optical disk system and including the step of generating a feedback signal to dynamically tune the signal output from a laser source, and including generating a plurality of timing signals serving to define a plurality of sampling windows for selecting data samples from RF signals derived from a signal reflected from the disc, generating a plurality of runlength selection signals to allow for measurement of light reflection at required runlength lands or pits, and measuring light reflected at a runlength land or pit in processing means and employing the measured signal as the said feedback signal for the said tuning of the signal source.

Abstract: The invention provides for a method and apparatus for writing data to an optical disc and comprising recovering an output signal from optical reading head, scaling the said output signal responsive to secondary data derived from the disc by way of the optical reading head and deriving a Land Pre Pits (LPP) signal for use during recording to the disc from the said scaled output signal wherein the said scaling is arranged to increase the LPP signal when the LPP is identified as located adjacent a mark on the disc of low light reflectivity.

Abstract: The invention provides for a method, and related apparatus, of producing a Land Pre-Pit signal during playback of an optical disc and including the steps of obtaining an output signal from an optical detector and from which the Land Pre-Pit signal is to be derived, scaling the said output signal responsive to a determined amplitude of a high frequency crosstalk signal arising during reading of the disc and in a manner so as to increase the said output signal when the Land Pre-Pit identified as corresponding to a mark on the disc, and so as to decrease the output signal when the Land Pre-Pit is identified as corresponding to a space on the disc.

Abstract: The present invention provides for an optical pick-up unit having a lens arrangement for driven movement in the direction of an optical disk, a counterweight mass member mounted in a manner so as to be moveable in the direction of the disk when the optical pick-up unit experiences an impact force, such as, for example, if it is dropped, the mass and lens arrangement each having respective engagement formations arranged to achieve contact during movement of the lens arrangement and the mass member in the relative direction of the disk such contact serving to arrest the movement of the lens arrangement in the said relative direction of the disk.

Abstract: The invention provides for a method, and related apparatus, of producing a Land Pre-Pit signal during playback of an optical disc and including the steps of obtaining an output signal from an optical detector and from which the Land Pre-Pit signal is to be derived, scaling the said output signal responsive to a determined amplitude of a high frequency crosstalk signal arising during reading of the disc and in a manner so as to increase the said output signal when the Land Pre-Pit identified as corresponding to a mark on the disc, and so as to decrease the output signal when the Land Pre-Pit is identified as corresponding to a space on the disc.

Abstract: The present invention provides for an apparatus and method of controlling writing a signal to an optical disc in an optical disk system and including the step of generating a feedback signal to dynamically tune the signal output from a laser source, and including generating a plurality of timing signals serving to define a plurality of sampling windows for selecting data samples from RF signals derived from a signal reflected from the disc, generating a plurality of runlength selection signals to allow for measurement of light reflection at required runlength lands or pits, and measuring light reflected at a runlength land or pit in processing means and employing the measured signal as the said feedback signal for the said tuning of the signal source.

Abstract: The invention provides for a method and apparatus for writing data to an optical disc and comprising recovering an output signal from optical reading head, scaling the said output signal responsive to secondary data derived from the disc by way of the optical reading head and deriving a LLP signal for use during recording to the disc from the said scaled output signal wherein the said scaling is arranged to increase the LLP signal when the LLP is identified as located adjacent a mark on the disc of low light reflectivity.

Abstract: The invention provides for a method and apparatus for of processing digital data (10), comprising the steps of forming a plurality of discrete bursts of data (12) from the digital data, charging a charge storage device (32) during periods (14) between the discrete bursts of data, and subsequently discharging the charge storage device (32) during the discrete bursts of data (12) so as to provide at least part of the power required during the data bursts (12) and so as to reduce peak power requirements while allowing for the transfer of data at rates less than a minimum data rate set for data recordal/playback

Abstract: A method of retrieving data from a record carrier disc having rotary information tracks on which the data is recorded. A read head reads data from the tracks into a buffer memory, from which it is supplied to an output terminal. This permits continuous playback of the recorded information during temporary intervals when, due to mechanical shocks, the read head becomes misaligned relative to the tracks. After such a misalignment the read head becomes realigned at a subsequent track position, and as soon as data is again being correctly detected it is written into the buffer memory in a location therein which leaves a gap between the currently written data and that written before the shock occurred. When the disc rotation brings the read head into radial alignment with the position where the shock commenced, the read head is moved inward to return to that position and the gap in the buffer memory is filled by reading from the disc the data which was missed during the misalignment following the shock.