Abstract: An interactive subscriber telephone terminal, comprising: a display screen; a plurality of temporarily definable response/data entry keys; and local control means for selectively causing the display screen and/or the response/data entry keys to be controlled by one of: remote signals transmitted to the terminal from a telephone switching office, and the local control means.

Abstract: A a series of m-bit information words is converted to a modulated signal. For each information word from the series, an n-bit code word is delivered. The delivered code words are converted to the modulated signal. The code words are distributed over at least one group of a first type and at least one group of a second type. When a code word belonging to a group of the first type is delivered, its group establishes a coding state of a first type. When a code word belonging to an group of the second type is delivered, a coding state of a second type is established which is determined by the information word which is to be converted to the delivered code word. When one of the code words is assigned to the received information word, this code word is selected from a set of code words which depends on the coding state established. The sets of code words belonging to the coding states of the second type are disjunct.

Abstract: An encoder apparatus is disclosed for encoding a wideband digital information signal. The apparatus comprises an input signal (1) for receiving the wideband digital information signal, a signal splitting unit (2) for splitting the wideband digital information signal into M narrow band sub signals (SB.sub.1 to SB.sub.M). The narrow bands all have a specific constant bandwidth. Further, a scale factor determining unit (6) for determining a scale factor for subsequent signal blocks in each of the sub signals, and a quantization unit (13) for quantizing the samples in a signal block into quantized samples are present. A bit allocation information deriving unit (34,41,48) is present for deriving bit allocation information, the bit allocation information being representative of the number of bits with which samples in a signal block of a sub signal will be represented after quantization in the quantization unit (13).

Abstract: Television tuning systems and methods employing use of ghost cancellation and antenna directionality control to produce a ghost-free television signal. The invention employs use of a antenna whose directionality can be changed to change reception quality of a received television signal, and a baseband ghost cancellation unit which can perform baseband ghost cancellation. In a first embodiment of the invention, the directionality of the antenna is changed so that a television signal of sufficient reception quality is received from which a ghost-free television signal can be produced therefrom by the baseband ghost cancellation unit. A second embodiment of the invention further employs use of a tuner, and involves controlling the directionality of the antenna and the tuning frequency of the tuner so that a tuned television signal is produced which is properly tuned and of sufficient quality that a properly tuned ghost-free television signal can be produced therefrom by the baseband ghost cancellation unit.

Abstract: For encoding sound received as a stream of multibit input sample, from a finite length sequence of input samples, an instantaneous audibility threshold characteristic is determined. Next, a shaped, dither determined, signal is subtracted from the input samples to produce processing samples. Subtracting a dither signal dynamically ignores processing sample bits below the threshold. Next, quantization by a variable number of bits below the threshold is performed, while retaining all sample bits above the threshold. The ignored bits are replaced by the dither signal as buried channel bits at an adjustable number of bits per sample. Therefore, upgraded samples have non-ignored bits and buried channel bits are obtained and outputted. The noise is shaped through shape-filtering a difference between the upgraded samples and the processing samples, which shape-filtering may amend a received white-noise-like signal towards an actual threshold-versus-frequency characteristic.

Abstract: A sequence of m-bit information words is converted to a modulated binary signal. For each received information word from the sequence an n-bit code word is delivered. The delivered code words are converted to the modulated signal. When one of the code words is assigned to an information word to be converted, this code word is selected from a set of code words that depends on a coding state which is related to a digital sum value at the end of the modulated signal that corresponds to the previously delivered code word. From at least one of the digital sum values, a first or a second coding state of a pair of coding states of a first type is determined. Which of the two coding state of the pair is determined depends on the information word that corresponds to the previous delivered code word. The sets of code words belonging to the pairs of coding states of the first type contain no code word whatsoever in common.

Abstract: A receiver including an error masking unit for masking an error in a digital signal received by the receiver, and a transmission system including such a receiver. The transmission system includes a transmitter which sub-band codes a wide-band digital signal into sub-band signals having signal blocks containing a predetermined number of samples which the transmitter quantizes and combines with bit allocation information denoting how many bits each of the samples in the signal blocks are quantized by and scale factor information relating to scale factors for the signal blocks into a digital signal. That digital signal is error correction encoded and then applied to a transmission medium by the transmitter. The receiver receives a digital signal from the transmission medium which substantially corresponds to the digital signal applied to the transmission system by the transmitter and decodes that digital signal so as to produce a replica of the wide-band digital signal encoded by the transmitter.

Abstract: A scanning device for repeatedly scanning a scanning surface of a record carrier (e.g., a tape) by means of a first and a second scanning spot produced by respective scanning beams. The scanning spots perform synchronous movements along a first and a second scanning path, respectively, having different given scanning directions, as a result of which, the distance, viewed in a direction transverse to the scanning paths, between the first and the second scanning spot changes during scanning. The scanning device can be used in a recording and/or read apparatus which further includes a detection system for converting radiation emanating from the second scanning spot into a corresponding detection signal, and a measurement circuit which derives a position measurement signal indicative of deviation of track pitch based on a deviation in a relationship between the detection signal and a reference signal indicative of the position of the first scanning spot on the first scanning path.

Abstract: The invention relates to an optical unit for generating an optical data signal in conformity with a data pattern. The unit has an input for receiving the data pattern with a modulation period T, a pulsed laser for supplying an optical pulse series having a pulse period n.T and a pulse duration .tau., in which n is an integer, and a converting unit for converting this pulse series into an optical data signal in conformity with the data pattern. The converting unit is a radiation-controlled optical switch. This switch has a first input for receiving the data pattern in the form of an optical pulse series whose pulses have a pulse width b, a second input for receiving the optical pulse series from the pulsed laser for sampling the data pattern during periods when the switch is open, and an output for supplying a data pulse series having a pulse width .epsilon..b, in which 0 <.epsilon.<1.

Abstract: An apparatus and method for recording an information signal on a record carrier by means of a radiation beam which produces optically detectable marks in parallel track portions thereon having a substantially constant track pitch (q). The write intensity of the radiation beam is adjusted to an optimum level which results in a width (p) of the optical marks which corresponds to the track pitch (q). The optimum intensity level is determined by recording different test signals in adjoining track portions at various write intensities of the radiation beam, reading-out the recorded test signals, and detecting therefrom the write intensity at which signal components of one test signal no longer occur in another recorded test signal. Recording at the optimum write intensity results in a minimum block error rate (BLER) upon read-out of the recorded information signal.

Abstract: Methods and apparatus for encoding and/or decoding digital data elements of a uniform size with different degrees of error protection in accordance with a quasi-product code.

Abstract: Subband coding a digital signal having a first and a second signal component in a stereo intensity mode. The digital signal is subband coded to produce a first subband signal having a first q-sample signal block in response to the first signal component, and a second subband signal having a second q-sample signal block in response to the second signal component, the first and the second subband signals being in the same subband, and the first and second signal blocks being time-equivalent. The first and second signal blocks are processed to obtain a minimum distance value representative of a distance between a line and a plurality of points if (a) the points correspond to the respective pairs of time-equivalent samples in the first and second signal blocks, and are plotted in a coordinate system, and (b) the line is plotted such that it traverses the origin and the points at a minimum distance from the points in the coordinate system.

Abstract: An arrangement for reading out an information signal from a magnetic record carrier. The arrangement includes a read head having a magneto-resistive (MR) element (R.sub.m1) with a first terminal (3) connected to a first point (13) of constant potential, and a second terminal (4); a bias-current generator (2) having an output (5) for supplying a bias-current to the MR element; and an amplifier circuit (1) having a first terminal (6) coupled to the output (5) of the bias-current generator (2), and a second terminal (7) coupled to the second terminal (4) of the magneto-resistive element (R.sub.m1) so as to form a series arrangement of the bias-current generator, the amplifier circuit and the magneto-resistive element. At an output terminal (8), the information signal is available. The amplifier circuit (1) includes a MOS transistor T.sub.1 coupled between the output terminal (8) and the second terminal (7), and a feedback circuit, including a resistor (R.sub.1) and a capacitor (C.sub.

Abstract: A polynomial divider which can perform Euclid's Algorithm by iteratively solving both equations thereof through performing iterations of polynomial division so as to produce an error locator polynomial from an error syndrome polynomial, and apparatus including the polynomial divider. The polynomial divider is capable of performing polynomial division of a numerator polynomial by a denominator polynomial to produce a quotient polynomial and a remainder polynomial.

Abstract: Apparatus and methods for improving timing recovery of a system clock by causing its frequency to be within a specified tolerance range during a timing recovery acquisition period for the system clock. The apparatus includes a voltage controlled oscillator for producing the system clock and a non-volatile memory containing an offset value. The non-volatile memory provides an offset value (representing an offset voltage value) which assures that the voltage controlled oscillator receives a voltage value which causes the frequency of the system clock to be within a specified tolerance range. The apparatus may also include a write control unit for determining and updating the offset value for a next timing recovery acquisition period. The methods include steps for performing these operations.

Abstract: A method and an apparatus for manipulating an input signal (e.g., an audio equivalent signal) having a specific length to form an output signal having a different length. A chain of successive overlapping time windows is positioned with respect to the input signal; segment signals are derived from the input signal and the segment signals; and the output signal is synthesized by chained superposition of a sequence of the segment signals. Each of the windows (except for the first window in the chain) is positioned by incrementing a position of the window from a corresponding position of a preceding window in the chain by a time interval. That time interval is substantially equal to a principal period of periodicity of a portion of the input signal with respect to which the window will be positioned. The sequence of segment signals is derived from the segment signals by performing at least one of repeating and suppressing one or more of the segment signals.

Abstract: Methods and apparatus for encoding and decoding an audio and/or video signal, and a record carrier for use with such apparatus. One or more audio and/or full motion video signals, e.g., a video signal (and possibly computer data), are recorded on an interactive compact disc. The video signal prior to being recorded is encoded into code blocks of variable lengths, each corresponding to a picture or picture pair. A decoder delay time parameter associated with one or more of the code blocks, which parameter represents a length of time (i.e., a delay time) with which the corresponding picture of a code block is to be displayed after that code block has been received by a decoding apparatus is determined and included in the video signal prior to being recorded.

Abstract: Methods and apparatus for encoding and decoding an audio and/or video signal, and a record carrier for use with such apparatus. One or more audio and/or full motion video signals, e.g., a video signal (and possibly computer data), are recorded on an interactive compact disc. The video signal prior to being recorded is encoded into code blocks of variable lengths, each corresponding to a picture or picture pair. A decoder delay time parameter associated with one or more of the code blocks, which parameter represents a length of time (i.e., a delay time) with which the corresponding picture of a code block is to be displayed after that code block has been received by a decoding apparatus is determined and included in the video signal prior to being recorded.

Abstract: A system for transferring audio and/or video information via an information carrier, e.g., DAT, CD or CDV. In the R-W subcode channels of a CD-signal, textual or visual information about the audio and/or video signal is recorded. This information is divided into packets. Packets containing information of different categories are interleaved. After reading the information from information carrier, the packets of a selected category are separated from information read. This system of transferring additional information (in packets) allows the use of a separate packet category for each of a number of different languages, so that a user can select a language with which he or she is most familiar. In addition, menu information, including coded menu text lines and command codes, can be recorded in the R-W subcode channels as packets for interactive control of the read-out of the audio and/or video information or the control of other connected devices.

Abstract: Method of deriving a quality signal for a binary read signal having bit cells of constant length, and reading and recording devices which employ that method. During a reading process, an information pattern of optically detectable effects, representing certain of the bit cells, is scanned. A read signal is generated therefrom in which first read signal portions that exceed a reference value correspond to the effects. The quality signal is derived (in an analysis circuit) from the first read signal portions based on a measure of the deviation of first read signal portions corresponding to a particular length or mutual differences between length deviation of first read signal portions of different lengths. The quality signal can be used for adapting a recording strategy used in the recording of information, or for setting an equalizing filter.