Abstract: On existing DVD and CD players a control loop is required for the adaptation and timing recovery. For Two-Dimensional Optical Storage such a control loop has drawbacks because PRML detection in the form of a stripe-wise Viterbi detector is used. Such a detector introduces an increasing detection delay when going from the outer rows towards the center of the broad spiral. A feedback loop is arranged to determining an error signal from a first area of the data block where the first area is that area where the error signal can be determined within the shortest period of time. This reduces the duration of the detection step and thus increases the stability of the control loop.

Abstract: In a method for coding an audio signal to obtain a coded bit stream, discrete-time samples of the audio signal are transformed into the frequency domain to obtain spectral values. The spectral values are coded with a code table having a limited number of code words of different lengths to obtain spectral values coded by code words, the length of a code word assigned to a spectral value being that much shorter the higher the probability of occurrence of the spectral value is. A raster is then specified for the coded bit stream, the raster having equidistant raster points and the distance between the raster points depending on the code table(s) used. In order to obtain error-tolerant Huffman coding, priority code words, which represent particular spectral values which are psychoacoustically more important than other spectral values, are so arranged in the raster that the start of each priority code word coincides with a raster point.

Abstract: A method and a device for entropy encoding and associated decoding make use of a code consisting on the one hand of a code table with reversible code words (12) and comprising on the other hand an escape region for information words to be coded which are located outside the region (14) defined by said code table. Said region can be selected in such a way that a major part of the information words is coded with symmetrical code words by the code table. On the one hand, it is thus possible to carry out, in addition to forward decoding, also backward decoding (24) and on the other hand, use of reversible code words allows for rapid recognition of errors in a code word stream transmitted over a non-ideal channel.