Method, apparatus and record carrier with average-runlength preserving code for improved readout parameter control

摘要

The present invention relates to a method and apparatus for controlling at least one readout parameter of a magneto-optical domain expansion recording medium. An average detected runlength of the reading signal is monitored, and an error signal is generated on the basis of a comparison of the monitoring result with the predetermined average runlength that has been set during the encoding step. The at least one readout parameter is then controlled by means of the generated error signal. Furthermore, the present invention relates to a method, apparatus and record carrier wherein a runlength constraint is applied to at least one of the following quantities: mark regions and space regions in said storage layer, said runlength constraint being selected to keep an accumulated runlength deviation from a predetermined average runlength within a predetermined range. The proposed runlength property and control scheme provide the advantage that all detected runlengths contribute to the error signal to make the response must faster and to reduce readout errors.