Abstract: A system for subband coding of a digital audio signal x(k) includes in the coder (1) a filter bank (3) for splitting the audio signal band, with sampling rate reduction, into subbands (p=1, . . . P) of approximately critical bandwidth and in the decoder (2) a filter bank (5) for merging these subbands, with sampling rate increase. For each subband (p) the coder (1) comprises a detector (7(p)) for determining a parameter G(p;m) representative of the signal level in a block (p;m) of M samples of the subband signal x.sub.p (k) as well as a quantizer (8(p)) for adaptively block quantizing this subband signal in response to parameter G(p;m), and the decoder (2) comprises a dequantizer (9(p)) for adaptively block dequantizing the quantized subband signal s.sub.p (k) in response to parameter G(p;m).

Abstract: An optical record carrier body having a planar substrate with elongated generally parallel servo tracks thereon separated by lands extending there-between, the lands having a flat surface coplanar with the substrate surface and a recording layer thereon on which information can be recorded by a beam of radiation. Sector addresses are provided between successive segments of the lands, each sector address having optically detectable areas. The maximum transverse width of each servo track is at least 60% of the track period and at least twice the maximum transverse width of the sector address areas. Apparatus is disclosed for recording the servo tracks and sector addresses on a substrate, as well as apparatus for recording information on the successive segments of the lands between the sector addresses.

Abstract: An input circuit to an active addressed display sequentially switches pixels of video information into high speed sample-and-hold elements which are coupled to corresponding signal lines on the substrate. The pixels of video information are on the signal lines for a complete switching cycle and are transferred to vertical source lines of the display during a time interval equal to the period of a switching cycle.

Abstract: Envelope detector comprising a differential amplifier (A), a full-wave rectifier circuit and a smoothing filter (AF), which differential amplifier (A) converts an input voltage into a pair of current signals in phase opposition and which full-wave rectifier circuit comprises a pair of half-wave rectifiers (HWR1, HWR2) for half-wave rectifying the said pair of current signals, coupled to a first combining stage (S) for combining the output signals of the two half-wave rectifiers (HWR1, HWR2) with like polarity, which first combining stage (S) supplies a full-wave rectified signal. In order to reduce d.c. offsets, the detector comprises a frequency-dependent negative feedback loop which comprises a second combining stage (D) coupled to the outputs (R.sub.o1, R.sub.o2) of the pair of half-wave rectifiers (HWR1, HWR2) for combining the output signals of the pair of half-wave rectifiers (HWR1, HWR2) with opposite polarity, said second combining stage (D) being negatively fed back to the input (I.sub.

Abstract: High transmission and reception quality is achieved in a high definition television system, with minimum intra-channel interference, by digitally encoding the enhancement information and employing spread-spectrum modulation techniques.

Abstract: Method and apparatus for synchronizing local clocks at each of two data stations. The first data station is connected through an analog network to an interworking unit. The second data station is connected through an integrated services network having a central clock, to the interworking unit. The interworking unit includes a comparator for comparing the clock phase from the first station transmit clock to the central clock. The result of the comparison is transmitted to the second data station for use in synchronizing the second data station to the first data station.

Abstract: In the method of adjusting the transmission of an electric signal, applied to an input terminal (1, 1'), via two transducer devices (8, 9), to an acoustic signal at two positions (P.sub.1, P.sub.2) in a space (10), (a) the levels of the electric signals applied to the two transducer devices are adjusted in such a way that the two transducer devices provide substantially equal contributions to the acoustic signal at the first position (P.sub.1), (b) the second filter unit (4) is adjusted so as to obtain a desired frequency-response characteristic (50, FIG. 5) for the transmission from the input terminal (1, 1') to the second listening position (P.sub.2), (c) the first filter unit (3) is adjusted so as to obtain a desired frequency-response characteristic (50, FIG. 5) for the transmission from the input terminal (1, 1') to the first listening position (P.sub.1). Also described are an arrangement for carrying out the method (FIG.

Abstract: A digital lattice filter, comprising a plurality of identical stages each having a pair of inputs for receiving input signals and a pair of outputs for supplying output signals, these stages being connected in a cascade arrangement, each stage consisting in two mutually linked branches and no less than one of these branches comprising delay means, and in that always an even number of successive cascaded filter stages forms a group, in which both branches of each group of filter stages comprise a delay elements such that the time delay in the first branch is equal to the time delay in the second branch.

Abstract: A PIN diode is in series in a high-frequency signal path between an input and an output, and is controllably biased either on or off by a control signal supplied thereto from the output of a control circuit in response to a command voltage. The control circuit derives the control signal from a positive voltage source when the diode is to be turned on and from a negative voltage source when the diode is to be turned off. The negative voltage must be a relatively high value, which can cause excessive power dissipation in the control circuit due to charging of the bypass capacitance present at the output terminal thereof for shunting high frequencies. To prevent that, the control circuit includes an overvoltage circuit which produces a short duration trigger pulse in response to change-over from the positive voltage source to the negative voltage source and which supplies a current pulse of brief duration for charging the bypass capacitance.

Abstract: An integrated optical device comprises stacked substrates provided with optical waveguides in different planes. The waveguides in different planes are interconnected by external optical elements.

Abstract: A circuit for decoding coded frequency modulated signals eliminates perturbing effects of noise pulse signals by coupling the signal to be detected through a filter having a transfer function that is related to the conjugated transfer function of the frequency modulation deemphasis filter, the spectrum of the noise pulse, the spectral power density of the signal to be demodulated, and the spectral power density of the noise. A comparison circuit provides the signal at the output of the filter when the output signal exceeds a threshold level. A decision circuit, which provides signals representative of the temporal position and polarity of the noise pulses to the correction circuit, is coupled between the comparison circuit and a circuit for generating noise correction pulses. The noise correction pulses are coupled to the decoder with the output signal of the detector to eliminate the effects of the noise pulse.

Abstract: A gyro stabilized optical radiation deflection device which provides a radiation sensitivity lobe which is stabilized against angular motions of the envelope in which the radiation is received or transmitted. Such device consists of a ball-shaped gyro rotor rotating about a spin axis and which is seated in a spherical recess in a support which is fixedly connected to the envelope. The central portions of the rotor and recess, through which the radiation is transmitted, are prisms which are transparent to the radiation. Such prisms together form an adjustable diffraction prism which serves as an optical wedge for directing the radiation in a directive sensitivity lobe, such direction being determined by the angle between a planar wall of the rotor prism and a planar wall of the recess prism.

Abstract: A pulse generator of controllable duty cycle for horizontal synchronization signals in a television receiver is provided. The pulse generator broadly comprises a duty cycle control loop with a comparator means having an output coupled to the output of the pulse generator, a duty cycle detector means coupled to the comparator means for detecting the duty cycle of the output of the comparator means, a duty cycle control means for setting the duty cycle of the output of the comparator means to a desired value, and an error feedback means coupled to the duty cycle control means, the duty cycle detector means, and the comparator means. Duty cycle control is achieved either by a control pulse or by means of a voltage divider which is coupled between a supply voltage and ground, with a voltage divider node connected to the base of the error feedback transistor. The comparator means, the duty cycle of which is the duty cycle of the pulse generator, is turned on by means of the voltage at its base dropping 0.

Abstract: A method of estimating motion in a picture sequence in which each picture is divided into blocks defined by two coordinates (m,n), respectively, indicating the row of the picture line in which the block is present and the row of the block on this m-th line. This method provides for:defining three groups for the blocks classified in fixed blocks, moving blocks and exposed blocks, in which groups the blocks are classified with a delay in accordance with the scanning of the picture by examining a given number of possible group sequences;constructing a classification tree whose 3.sup.

Abstract: Method and apparatus for extending the horizontal resolution of the luminance and chrominance video signals in a two-channel HDTV system, requiring no increase in channel bandwidth. High-frequency components of luminance and chrominance of a wide bandwidth source signal are bandpass filtered, vertically decimated, time expanded, and heterodyned into frequency interleaved relationship with each other and with a line differential signal to produce an enhancement package carried in a designated time and frequency slot on the second channel. At the receiver, the various signal components are recombined to substantially reproduce the source signal for display.

Abstract: The present invention discloses a noise measurement method and system in a television signal receiver. In the preferred embodiment, the receiver has a noise reduction circuit and receives a composite television picture signal which contains noise, picture information, a trigger pulse (preferably the V-sync pulse), a horizontal synchronizing pulse (at least once per television scan line) and a standard signal adjacent in time to and later than the horizontal synchronizing pulse. The preferred standard signal is a back porch signal or a color burst signal. A comparator receives at least two samples of the standard signal and produces a comparison signal that is representative of the comparison of the two standard signal samples. Preferably the two standard signal samples are from two different scan lines. An accumulator circuit receives the comparison signal and generates a measured noise signal that is used to control the noise reduction circuit.

Abstract: A microwave oven which provides defrosting control for a frozen product to be defrosted. The oven comprises a microwave source and a detector arranged in the oven cavity in the proximity of the frozen product, the detector including a material which absorbs microwave energy, the absorption of microwave energy by the detector and by the frozen product causing their temperatures to rise and thereby defrosting such product. Variations in the detector temperature are measured by a measuring element which provides an electrical signal corresponding thereto. The detector is configured and insulated so as to have a heat exchange characteristic with its environment which results in its temperature detection sensitivity remaining constant during each of a plurality of successive defrosting operations of the oven. A computer control device evaluates when a defrosting operation has been completed by determining when the slope of the signal variation as a function of time remains the same at successive sampling instants.

Abstract: A record carrier is described for optically writing and reading information, which record carrier is provided with a pre-formed track. This track is formed by a ridge disposedon the substrate surface and the recording layer comprises a dye layer having such a thickness at the location of the ridge that a write beam can produce a maximum optical effect therein, the dye layer being thicker at locations outside the ridge.

Abstract: A microwave oven which includes a defrosting detector in the oven cavity in the proximity of a frozen product to be defrosted, the detector including a material which absorbs microwave energy, the absorption of microwave energy by the detector and by the product causing their temperatures to rise. Variations in the detector temperature are measured by a measuring element producing an electrical signal corresponding thereto, such signal being used to control the defrosting process. The microwave absorbent material is in the form of a layer deposited on a carrier which is positioned behind the product so that most of the detector area can only receive microwave energy through the product, whereby the rate of change of detector temperature with time decreases as the product defrosts and becomes constant when defrosting has been completed. The carrier may be one of the walls of the oven cavity or the oven tray. The material may be a resistive ink deposited on the oven tray by screen-process printing.

Abstract: A microwave oven includes a microwave source and a defrost detector arranged in the oven cavity in the proximity of a frozen product to be processed, the absorption of microwave energy being distributed between the detector and the product and causing their temperature to rise, the temperature variation of the detector being measured by a measuring element producing a corresponding electrical signal. The oven also includes a computing control device which determines completion of defrosting of the product by computing the values at successive instants of the second derivative of such signal as a function of time. The computing control device controls the oven at the end of the defrosting cycle, which is when the value of such second derivative falls below a predetermined value.