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: Disclosed is a system for optically recording information on a disc-shaped record carrier body along an information track, with the write spot being accurately guided in the radial and tangential directions. The record carrier body comprises a servo track formed by a constant and large number of servo areas per revolution of the servo track. In addition to a write spot, the write apparatus also projects a servo spot on the servo track. The tangential speed and the radial position of the servo spot relative to the servo track are determined from the modulated servo beam and used to correct the tangential speed and the radial position of the write spot, which is locked to the servo spot.

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.

Abstract: A telephone instrument housing constructed from a first section (1) and a second section (2), the first. The second section (2) comprises three identical first sub-sections (4,5,6) which are substantially rectangular in plan. The number of first sub-sections is dependent on the dimensions of the first section (1) which is formed in one piece. The first sub-sections (4,5,6) comprise a first part defining a regular array of apertures (22, FIG. 2) suitable for locating an array of pushbuttons (8). The array of apertures (22) extends across the full width of the rectangle so that when two or more subsections are butted together a continuous regular array of apertures extends across the arrangement of first subsections. A cover plate (9) covers locations in which no pushbutton is provided, the cover plate being located by the apertures (22). The first sub-sections also comprise a second part defining a single aperture (14) which extends over a major portion of the second part.

Abstract: Apparatus for transferring data and other information between a data processing unit and a rectangular memory card which includes an optically readable data memory unit having a succession of substantially concentric data storage tracks thereon, the card also including at least one microelectronic component which stores further information. Such component is connected to connection points on the surface of the card. Data is read from the tracks of the memory unit by optical scanning during rotation of the card about the axis of symmetry of the memory unit, and information is transferred between the microelectronic component and the data processing unit by an information transfer unit which is coupled to the connection points on the card and to the data processing unit.

Abstract: An amplitude modulation apparatus characterized in that a high frequency modulation circuit is provided at the down-stream side of an automatic output control circuit which inputs a low frequency signal, the high frequency signal level of an output of said high frequency modulation circuit being detected to obtain a detection signal which activates said automatic output control circuit.

Abstract: The recording surface of an optical record carrier (1) is divided into a succession of first (A) and second (B) annular zones, each including a plurality of substantially concentric information tracks. The tracks in each zone (A) include radially aligned first control words (13) and the tracks in the annular zones (B) include radially aligned second control words (14), the structures of the first and second control words being distinguishable from each other. An optical scanning device projects a beam which as it scans the tracks reads the control words and a detection circuit generates a measurement signal V.sub.m upon each passage of the beam from one zone to another. The measurement signal can be utilized to rapidly address the scanning beam to any of the annular zones.

Abstract: A sensor (CTD) which is formed with pick-up elements (D) for converting incident radiation (L) into electric charge packets which can be shifted to a sensor signal output (TO) through sensor elements under the control of clock pulse signals (CS1) may be beset with unwanted signal smear caused by the shifting process. To eliminate this, the relevant pick-up device includes a signal smear reduction circuit (SRC) which is specifically operative for a smear component produced during instantaneous shifting after a radiation information integration period.

Abstract: A scanning unit for an optical disc record carrier includes a radiation-sensitive detection system having a plurality of detection elements on which is formed a reflected image of the scanning spot on the track structure of the record carrier. A tracking error signal is derived by combining the output signals of detection elements situated on respective sides of a boundary line between two halves of the detection system, and comparing with each other the combined signals from both halves. Several different such tracking error signals are derived, for boundary lines having different orietations with respect to the direction of the track instantaneously being scanned. The tracking error signal corresponding to a boundary line most nearly parallel to the direction of such track will be of greatest amplitude, and is selected as the tracking error signal used for controlling the scanning unit to follow the center line of such track.

Abstract: A radio transmission system a base station comprises a plurality of transmitters arranged to transmit from the same site and having substantially the same output power, each transmitting on an individual channel within a dedicated block of contiguous channels. Receivers tuned to channels within said block of channels therefore require a limited image and adjacent channel rejection, of the order of 30 db. The receiver is preferably a direct conversion phasing receiver which has a local oscillator which can be tuned to a frequency within the block such that an image of any channel also falls within the block of channels. The system is suitable for local area radio systems such as paging or cordless telephones.

Abstract: A method and apparatus for scanning a rotating optical disc record carrier with a radiation beam which forms a scanning spot on the carrier and which is moved radially relative thereto. Pulses are generated at a frequency proportional to the angular velocity of the carrier, and clock pulses are generated at a constant frequency differing from and preferably higher than that of the velocity pulses. In response to each velocity pulse an accumulator is incremented by a first correction value (INC) and in response to each clock pulse the accumulator is decremented by a second correction value (DEC). The angular velocity of the record carrier is controlled to maintain a constant value of the average of the sum output of the accumulator over the intervals between successive velocity pulses, and the correction values are adjusted so that the ratio thereof is maintained proportional to the radial distance between the scanning spot and the axis of rotation of the carrier.

Abstract: A circuit comprising a semiconductor photodiode with a first and a second terminal and an internal series resistor, including an amplifier with a first input, a second input and an output, the first photodiode terminal being connected to the first amplifier input, the second photodiode terminal being connected to the second amplifier input and a negative feedback being inserted between the output of the amplifier and its first input, characterized in that a coupling is introduced between the output and the second input of the amplifier, by means of which a voltage is generated between the second input of the amplifier and the second terminal of the photodiode, this voltage being oppositely equal to the product of the internal series resistance and the signal current flowing through the resistor.

Abstract: An optical record carrier having a surface layer which includes a substantially circular information track structure, such surface layer extending without interruption substantially up to the center of the track structure. When the record carrier is supported on a rotating turntable and scanned by a scanning beam producing a scanning spot having a width transverse to the track direction of at least a few times the period of the track structure, a diffracted beam is produced by the track structure in a direction transverse to the local track direction. A radiation-sensitive detection system in the path of the diffracted beam produces output signals indicating any centering error between the center of the track structure and the axis of rotation of the turntable. Such signals can be employed to control positioning means to position the record carrier on the turntable so as to eliminate such centering error.

Abstract: Method and apparatus for deriving flow information from magnetic resonance signals. A magnetic field gradient extends in the direction of the flow to make the magnetic resonance signals flow sensitive. In order to reduce the effect of relaxation times on the flow information an additional magnetic field component--a gradient or an r.f. signal--is applied which artificially reduces the relaxation times.

Abstract: A method of manufacturing an optical master disk, matrix derived from the master disk and synthetic resin information disk derived from the matrix.A method of manufacturing an optical master disk in which a supporting plate is provided on one side with at least two layers of a photosensitive material in which, taken from the supporting plate, the photosensitivity of the material of the layers increases and/or in which a light-absorbing separation layer is used between the layers, as well as a metal matrix derived from the master disk and an optically readable information disk of synthetic resin derived from the matrix.

Abstract: An error supervision circuit for a non-encoded binary bit stream running through an elastic store comprising a memory having n locations, the bit rate of the stream supplied to the input of the memory differing from the bit rate of the stream produced at the output thereof. The successive bits in each group of n bits of the input stream are respectively written into the respective memory locations by write clock pulses supplied by a write register, at the input rate, and are successively read out from such locations by read clock pulses supplied by a read register at the output rate. The higher rate register is periodically interrupted for one or more bit periods to equalize filling and emptying of the memory. The bit streams at the input and output of the memory are supplied to respective data inputs of a comparator. A clock output of the lower rate register is connected to a first control input of the comparator to intermittently open a time window therein for receiving n bits of the lower rate bit stream.