Abstract: A data processing apparatus includes an input terminal for receiving an audio signal, a 1-bit A/D converter for A/D converting the audio signal so as to obtain a bitstream signal, and a prediction unit for carrying out a prediction step on the bitstream signal so as to obtain a predicted bitstream signal. The data processing apparatus further includes a signal combination unit for combining the bitstream signal and the predicted bitstream signal so as to obtain a residue bitstream signal, and an output terminal for supplying the residual bitstream signal. A recording apparatus or a transmitter apparatus can use the data processing apparatus.

Abstract: A digital information signal is compressed into an encoded signal and coefficient data. The coefficient data is predicted, yielding a prediction signal. The coefficient data and the prediction signal are combined to a data signal. Both the encoded signal and the data signal are transmitted via the transmission medium.

Abstract: Audio signals are converted from analog into digital using the well-known sigma-delta modulation techniques. The digital signal then consists of a sequence of 1-bit samples at a frequency of e.g. 2822400 Hz (=64*44100 Hz). Lossless coding techniques are used to reduce the required storage- or transmission-capacity for these 1-bit oversampled audio signals. The performance (compression ratio) of the lossless coder for 1-bit oversampled audio signals is improved by sometimes overruling the probability signal for the lossless coder.

Abstract: An apparatus for data compressing an analog audio signal includes an input terminal for receiving the audio signal and a 1-bit A/D converter for A/D converting the audio signal to a digital bitstream signal. The apparatus has a lossless coder for lossless data compression of the bitstream signal to a data compressed bitstream signal, and has an output terminal for supplying the data compressed bitstream signal. A recording apparatus and a transmitter apparatus use the data compression apparatus. An apparatus for expanding the data compressed bitstream signal to a replica of the analog audio signal is used by a reproducing apparatus and a receiver apparatus.

Abstract: A data compression apparatus is proposed for data compressing at least a first and a second digital information signal (L0,L1,L2, . . . ,R0,R1, R2, . . .), each of the at least two digital information signals comprising subsequent samples. The apparatus comprises an input (1,2) for receiving the first and second digital information signal, a merging unit (6) for merging the samples of the first and second digital information signal after each other into one datastream so as to obtain a composite information signal (L0,R0,L1,R1,L2,R2, . . .). Further, a data compression unit (12) is available for data compressing the composite information signal so as to obtain a data compressed composite information signal and an output (16) is present for supplying the data compressed composite information signal.

Abstract: A data processing apparatus is disclosed for data processing an audio signal. The data processing apparatus comprises an input terminal (1) for receiving the audio signal, a 1-bit A/D converter (4) for A/D converting the audio signal so as to obtain a bitstream signal, a prediction unit (10) for carrying out a prediction step on the bitstream signal so as to obtain a predicted bitstream signal, a signal combination unit (42) for combining the bitstream signal and the predicted bitstream signal so as to obtain a residue bitstream signal, and an output terminal (14) for supplying the residual bitstream signal (FIG. 1). Further, a recording apparatus (FIG. 4) and a transmitter apparatus (FIG. 5) comprising the data processing apparatus are disclosed. Other data processing apparatuses can be found in the FIGS. 18, 19 and 20.

Abstract: A data compression apparatus is disclosed for data compressing a plurality of information signals. The data compression apparatus comprises input terminals (1,2) for receiving the information signals, prediction units (6,8) for carrying out a prediction step on the plurality of information signals so as to obtain a plurality of prediction signals, probability signal determining units (12,14) for generating in response to the plurality of information signals a corresponding plurality of probability signals, a first switching unit (4) for each time selecting a symbol in one a plurality of input signals applied to the first switching unit, a second switching unit (10) for each time selecting a probability signal corresponding to the symbol selected by the first switching unit, a control signal generator unit (24) for generating switching control signals for the first and second switching units (4,10), a lossless coding unit (18) and an output terminal (22) for supplying said data compressed output signal.

Abstract: The invention relates to the coding of digital information signal blocks comprising representation symbols, such as sampled values, by means of an adaptive variable-length coding, such as Huffman coding. The JPEG Standard also utilizes adaptive Huffman coding but the coding in accordance with this standard is inefficient when a comparatively large number of Huffman coding tables are to be transmitted. According to the invention, in the case of a small number of representation symbols per information signal block, the probabilities of occurrence of each of the representation symbols are transmitted together with the variable-length-coded representation symbols, a similar (de)coding table being generated both in the encoder and in the decoder on the basis of said probabilities.

Abstract: Method of embedding watermarks in a signal encoded by an encoder having a feedback loop, for example, a sigma-delta modulator (21,22,23). A digital watermark pattern (w) is embedded in the signal (z) by modifying selected samples (for example, replacing every 100th bit) of the encoded signal (y) by samples of the watermark pattern. The circuit (24) for modifying the samples is located inside the loop of the encoder. The effect of watermarking is thus compensated in subsequent encoding steps and the signal-to-noise ratio is only slightly affected.

Abstract: A data compression apparatus for data compressing a digital information signal obtained from a digital audio signal. The digital information signal includes p-bit samples, where p is an integer larger than 1. The apparatus has an input (16) for receiving the digital information signal, and a lossless compression unit (18) for carrying out a substantially lossless compression step on the digital information signal so as to obtain a data compressed digital information signal. The lossless compression unit includes a Rice encoder, which is distinguishable by a code parameter m. Further, an output terminal (22) is available for supplying the data compressed digital information signal. The Rice encoder has a generator unit (30) for generating the code parameter m from N samples of the digital information signal, in accordance with a formula which optimizes the value of m for each frame of N samples.

Abstract: A disc-shaped information carrier with a substrate and an information layer which includes optically readable elementary marks having a substantially uniform density. The information layer includes a first portion suitable for being read out at a first read-out speed and a second portion suitable for being read out at a second read-out speed higher than the first read-out speed. According to the invention, the second portion of the information layer is at a greater distance to a center of the disc-shaped information carrier than is the first portion of the information layer. A range of rotational speeds which an optical read-out unit must have for a full and correct read-out of the information carrier is reduced in this manner.

Abstract: In a the receiver, a reception signal is digitized (5) with a relatively high sampling frequency. Analog filters (2, 4) prevent aliasing. The digitized reception signal is applied via a splitter (100) to a quadrature digital signal processor (9, 10, 11, 12). In this processor, a desired carrier is selected and demodulated. The splitter (100) transforms the digitized reception signal in accordance with a first and a second transform function (H.sub.1, H.sub.2) to obtain in-phase and quadrature components (xi, yi), respectively. The sampling frequency is reduced (130, 140) in the splitter. A specific relation between the phase and magnitude of the transform functions (H.sub.1, H.sub.2) prevents aliasing. Such a relation can be achieved with relatively simple digital filters (110, 120).

Abstract: A digital transmission system is disclosed having a transmitter (3,6,9) and a receiver (13,16,19) for transmitting a digital signal, such as a digital audio signal, having a given sampling rate F.sub.S. The digital signal is subband coded into M subbands with sampling rate reduction. To that purpose the transmitter includes a first unit (3) for splitting up the digital signal into M signals having a sampling rate F.sub.S /M. These signals are available at the outputs (4.1 to 4.M) of the first unit (3), and are applied to M analysis filters (6.1 to 6.M), each filter (6.m) having one input (5.m) and two outputs (7.ma and 7.mb). The 2M filter outputs are coupled to 2M inputs (8.1 to 8.2M) of a signal processing unit 9 which has M outputs (10.1 to 10M) for supplying the M subband signals (S.sub.1 to S.sub.M). Each filter (6.m) is adapted to apply two different filterings on the signal applied to its input and to supply the two different filtered versions of the input signal to its two outputs.

Abstract: A time switching method and apparatus for exchanging data words from a sequence of time slots in an incoming time-division multiplex frame to any other sequence of time slots an outgoing time-division multiplex frame. A data word in a given time slot s in an incoming frame is stored in a memory at an address A(s) which is equal to the number of time slots D.sub.j in an outgoing frame for which j is less than s and for which D.sub.j exceeds D(s). The data word already in the memory location address A(s) and the data words in addresses higher than that address are each shifted to the next higher address. Data words at memory addresses lower than A(s) are maintained at such addresses.

Abstract: The invention relates to a broad-band, time-division multiplex, token-passing, ring local area network, with which both circuit-switched and packet-switched traffic, namely data, text, picture and speech traffic can be supported. The invention has for its object to provide a method of transmitting digital information in a ring having a comparatively high transmission capacity with which rapid access to the common ring transmission means can be obtained, without however high requirements being imposed on the processing speed of the stations. According to the invention this is in principle achieved by means of a method which guarantees that per time-division multiplex frame only one time slot, which is known to the station, needs to be accessed.