Abstract: A method for generating modem transmission signals with quadrature amplitude modulation (QAM) wherein scanned values of elementary bandpass signals are stored in digitally coded form, the elementary bandpass signals are weighted with coefficients depending on the information to be transmitted and the modem transmission signals are formed by superposition of the thus weighted elementary bandpass signals; and wherein in the case of n-PSK modulation, where n=4, 8, 12, 16 . . . , the phase positions of all elementary bandpass signals are selected such that the phase diagram is symmetrical to the axis .phi.=0, and no elementary bandpass signal coincides with the axis .phi.=0; 1/4n elementary bandpass signals, which cannot be derived from any other bandpass signal of phase diagram neither due to symmetry with the axis .phi.=0 or the axis .phi.=90.degree., respectively, nor by symmetry to the origin of the diagram, are stored in a digital memory; and the remaining, e.g.

Abstract: A magnetically controllable variable resistor comprises two separate elements between which a layer applied to at least one of the elements and a material with a magnetically variable specific resistance is sandwiched under mechanical pressure at least one of the elements having at least three tapering structures on its surface adjacent to the layer so that pressure contacts are formed in the region of these structures.

Abstract: A playback instrument for a record disc, the instrument including a turntable for supporting the disc to be played on which the disc is centered by means of a central bore, is provided with two annular, concentrically disposed, radially spaced flat bearing surfaces mounted on the turntable for the disc, the surfaces forming a rigid support, one bearing surface being disposed in the vicinity of the location of the center of such disc and the other bearing surface being disposed radially to the outside of the one surface at a distance from the location of the center of such disc, and disc holding components provided for exerting on such disc an attracting force of such magnitude as to cause the disc to contact the bearing surfaces over the entire area thereof.

Abstract: The X-ray apparatus of the present invention comprises a metal cylindrical wall member having a longitudinal axis and opposite open ends. A pair of end members is positioned within the open ends of the wall member, at least one of the end members being an annular ceramic member having a central aperture therein and being sealed at its outer periphery to the wall member. An anode and a cathode are located within the wall member and high voltage leads are connected to the anode and cathode, at least one of these leads passing through the aperture in the ceramic member in a vacuum-tight manner to form a vacuum-tight envelope comprising the wall and end members. At least one connecting member is releasably attached to an end of the wall member adjacent the annular ceramic member thereby providing an axial releasable electrical connection with a high voltage lead.

Abstract: A circuit for generating a direct control voltage dependent on an alternating voltage, particularly for the generation of a direct control voltage in a system for dynamic compression and expansion, including a storage capacitor for providing the control voltage, at least one electronically controllable charging circuit and at least one electronically controllable discharging circuit connected to the storage capacitor, a comparator for comparing an alternating voltage input signal with a reference value, first and second control circuit paths for connecting the output of the comparator to the control inputs of the charging circuit and the discharging circuit respectively, a time-delay circuit connected in one of the control circuit paths, and an inverter connected in one of the control circuit paths so that the output signals from the two control circuit paths are inverted with respect to one another.

Abstract: In a circuit system for the generation of a direct control voltage dependent upon an alternating voltage for a dynamic compander device, the system including a charging capacitor, a charging circuit connected to charge the capacitor, and a circuit connected to discharge the capacitor, a comparator unit is connected to effect comparison between the alternating voltage and a reference voltage and to produce an output voltage representative of the amount by which the alternating voltage exceeds the reference voltage, and at least one of the circuits is formed of a current source and an electronically controllable current path connected between the source and the capacitor and having a control input connected to the comparator unit for varying the conductance of the current path as a function of the output voltage of the comparator unit.

Abstract: A microwave oven has a cooking chamber provided with a microwave window covered by a glass-ceramic plate with the interposition of a seal. A microwave connecting housing adjoins the window externally of the cooking chamber. A microwave generating and guiding device bounds at least in part the space defined by the connecting housing for directing microwave energy into the cooking chamber. Further, an electric resistance heater is arranged in the cooking chamber. There are provided air inlet openings communicating with the space defined by the connecting housing for introducing pressurized air thereinto, whereby an air pressure is generated in the connecting housing for preventing cooking vapors and the like from reaching and soiling microwave generating and guiding components.

Abstract: A control voltage generator is described for a system for dynamic compression and/or expansion. The voltage generator has a series circuit consisting of a first controllable amplifier and a first rectifying circuit and a further controllable amplifier in the intelligence signal path. For effecting a rapid matching of the control voltage when the input signal suddenly increases in amplitude a further rectifying circuit is provided. The input of the further rectifying circuit is connected to the signal path before the first controllable amplifier and the output to the output of the first rectifying circuit.

Abstract: Digital information transmission system components including at least one unit arranged to transmit signal elements in parallel, at least one unit arranged to receive signal elements in parallel, and a corresponding plurality of signal transmission paths connected between such units to each convey a respective one of the signal elements, in which a unit serving to transmit such signal elements is constructed for selectively creating, in each path, a signal element in the form of a signal state representing either one of two binary values or a signal state different from that representing either such binary value; and a unit serving to receive such signals is constructed for producing a response which distinguishes between the appearance, in each path, of either binary value state or the different state.

Abstract: In a circuit including a semiconductor switch for switching a load current, the so-called storage time of the semiconductor switch, i.e. the delay occurring during switching from the conductive state to the blocking state, is regulated so as to decrease undesired variation of same, i.e. the storage period is maintained substantially constant. This is achieved in the case, for example, of a transistor in that, dependent on the collector voltage, the control or base current for switching on the transistor, and possibly a reverse base voltage applied to block the transistor, are varied so as to maintain the storage period at a desired value.

Abstract: In a circuit for the generation of a direct control voltage dependent upon an alternating voltage the changing of the control voltage is delayed after a rapid decrease in the alternating voltage amplitude. This delay time is controllable in dependence upon the time difference between an increase and a rapid decrease of the alternating voltage amplitude.

Abstract: A negative semiconductor resistance comprises two separate semiconductor elements of the same conductivity characteristic and with at least three areas of contact of a diameter less than 1.10.sup.-2 cm, a voltage being applied to the semiconductor elements such that it generates an electrical field which is greater than the breakdown field strength at the contact areas.

Abstract: In a microwave circuit for a parametric upper sideband down converter with real image frequency termination conductance, including a pump circuit supplying a pump signal, a parallel circuit at its input, an intermediate frequency circuit at its output, and a reactance diode coupling the parallel circuit and intermediate frequency circuit together, the parallel circuit is tuned approximately to the frequency of the pump signal; the intermediate frequency circuit is composed of a .pi.

Abstract: A circuit for switching and transmitting alternating voltages comprise an MOS transistor, the pn-junctions which surround the source and drain regions being biased in a blocking direction in the driven condition of the transistor, correspondence between the potential difference between gate and alternating voltages and the required drive voltage of the transistor being achieved by a circuit which largely synchronizes gate voltage changes with the alternating voltage to be transmitted.

Abstract: A circuit arrangement for feeding a module requiring a constant operating voltage in a user station fed by a current-conducting connection path, composed of: components defining a current control unit connected for controlling the current in the connection path; components defining a resistance control unit connected for controlling the alternating current resistance presented by the circuit arrangement to the connection path; a first current conducting branch connected for feeding current supplied by the connection path to the module; a second current conducting branch connected for conducting current supplied by the connection path in a manner to bypass the module; and a signal responsive switch connected for establishing current flow between the connection path and a selected one of the branches.

Abstract: In a method for controlling a switching regulator composed of a controllable electronic switch and a transformer, in which the electronic switch forms a series path with the transformer primary, the series path is connected in series between a direct voltage source and a load, and the amplitude of the current flowing through the switch constitutes a criterion for controlling the load voltage, which method includes periodically causing the switch to assume one switching state at regular intervals occurring with a predetermined frequency, comparing the value of a comparison voltage corresponding to the load voltage and having a selected nominal value with a second voltage value, and causing the switch to assume its opposite switching state when a predetermined relation exists between the comparison voltage value and the second voltage value, the second voltage value is defined by the sum of the values of a constant reference voltage, a control voltage which varies as a function of the current induced in the tra

Abstract: A mixer/oscillator circuit comprises a mixer stage to which an oscillator stage is connected, an emitter follower circuit being connected between the oscillator stage and the mixer stage.

Abstract: A measuring sensor having a temperature-dependent conductivity and composed of a shaped body of a solid electrolyte material exhibiting such temperature-dependent conductivity, and two contact layers sintered onto the body and arranged for connection to circuit conductors.

Abstract: Circuit for automatic dynamic compression an/or expansion. The circuit has adjusting member (10) for varying the propagation constant in a useful signal path and a further similar adjusting member (30) for varying the propagation constant in a branch path which serves for deriving a control voltage which is applied to the control inputs (11,31) of the adjusting members (10,30) in the useful signal path and in the branch path. Further the circuit has a lowpass circuit (20 . . . 26) which is connected to the adjusting member (10) located in the useful signal path. The circuit can be changed over to a different compander characteristic when the adjusting member (10) located in the useful signal path is connected up as a controllable highpass (10,15). The limiting frequency is of the order of magnitude of the limiting frequency of the lowpass circuit (20 . . . 26).

Abstract: In a superheterodyne signal receiver including an input circuit arranged to be tuned to a frequency to be received and including a signal controllable variable reactance element presenting a reactance whose value is adjusted by a tuning signal and determines the frequency to which the input circuit is tuned, and a controllable local oscillator producing an alternating signal to be mixed with a received signal to produce an intermediate frequency received signal, a tracking circuit composed of: a first frequency control circuit including the local oscillator; a second frequency control circuit including a controllable sampling oscillator and a member connected to respond to the frequency of the output from the sampling oscillator to derive a signal related thereto and supplying that signal, as the tuning signal, to the controllable element; and a control signal generating unit generating first and second control signals and connected for supplying the first control signal to the first frequency control circuit