Device for reading from and/or writing to optical recording media
AssigneeDeutsche Thomson-Brandt GmbH
InventorMichael Grimm
Life of this patent
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Abstract
A device is disclosed for reading from and/or writing to optical recording media, which has a scanner whose output is connected to the input of an analogue-to-digital converter, whose output is in turn connected to the input of a mirror signal detector. The device is able to generate a reliable mirror signal even at relatively high track crossing frequencies. The mirror signal detector has at least one element which is variable as a function of frequency.
Claims17
A device for reading from or writing to optical recording media, which has a scanning means, whose output is connected to the input of an analogue-to-digital converter, whose output is in turn connected to the input of a mirror signal detector, wherein the mirror signal detector has at least one element which is variable as a function of frequency.
A method for the frequency-dependent formation of a parameter mirror signal in a device for reading from or writing to optical recording media, comprising the following method steps:
- a) forming an envelope signal from a data signal;
- b) filtering the envelope signal taking account of a cut-off frequency;
- c) comparing the filtered envelope signal with a threshold values
- d) setting the parameter mirror signal to a first value if the filtered envelope signal lies above the threshold value, and to a second value if it lies below the threshold value;
- e) determining the frequency of the mirror signal;
- f) changing the value of the cut-off frequency as a function of the frequency of the mirror signal;
- and
- g) branching to step a).
A method for identifying an optical recording medium type by means of a parameter mirror signal in a device for reading from or writing to optical recording media, which device has a scanning means, whose output is connected to the input of an analogue-to-digital converter, whose output is in turn connected to the input of a mirror signal detector, and wherein the mirror signal detector has at least one element which is variable as a function of frequency, wherein a threshold value is specified and a check is made to see whether a mirror signal can be formed with regard to the threshold value, and in that the type of recording medium is determined from this information.
Dependencies are inferred from the claim text.