Abstract: A modular loudspeaker comprises a first module including a first loudspeaker unit (1) for reproducing a low-frequency audio signal and provided with at least two flat diaphragms (4, 5) and a second module including a second loudspeaker unit (2) for reproducing a high-frequency audio signal by means of a loudspeaker (8). The first and second loudspeaker units are constructed either to be mechanically detached from one another or to have connecting means whereby they can be rigidly mechanically connected to one another in a manner that will permit relatively easy mechanical detachment of the units from one another. Connecting means (10 or 11) allows the loudspeaker units to be electrically connected to one another and comprise interengageable parts that can be disengaged to disconnect the units.

Abstract: The invention relates to a charge detector, more particularly for reading binary information in a CTD. The detector includes a flipflop having two cross-coupled MOS transistors and two MOS transistors acting as loads. The signal to be read and the reference signal are supplied to the gates of the loads. The junctions between the driver transistors and the loads are connected to reset transistors. The drains of the loads are applied to a (fixed) supply voltage and the sources of the driver transistors are applied via a switching transistor to the supply voltage return. The circuit arrangement is operated so that before the activation of the flipflop the said junctions are set to a signal-dependent preadjustment. When the switching transistor is then energized, the flipflop will be in the correct stage with a higher degree of reliability and without being influenced by clock cross-talk.

Abstract: A circuit for switching a current in an inductive load comprising at least one transistor (1) which switches through its collector-emitter path the current in the load (7). The base is coupled to the emitter through a voltage-stabilizing element (5) for stabilizing the voltage supplied to the base. A dissipation device is usually added to the circuit for dissipating currents or voltages occurring in a sense opposite to the sense of conduction of the transistor (1). A simplification of the circuit and hence a decrease in the cost thereof is achieved in that the voltage-stabilizing element (5) also serves as the dissipation device.

Abstract: An electron image projector for transferring mask patterns onto a semiconductor wafer comprises a patterned photoemissive cathode mask (4) and a target (3) formed by the semiconductor wafer (11) coated with an electron sensitive resist (10). Accelerated by a uniform electric field E and focussed by a uniform magnetic field H a patterned electron beam is projected from the cathode onto the target with unity magnification. The electric field E is established between the cathode and an electron permeable anode grid (2) situated between the cathode and the target. The anode grid comprises a plurality of mutually parallel slats (21,31) spaced apart by elongate electron permeable regions (22,32). The grid may be formed for example by an apertured silicon wafer (see FIG. 2) or conductive sheet, or by metal wires stretched across a metal annulus (see FIG. 3).

Abstract: Apparatus for igniting and operating a high pressure arc discharge lamp includes a pulse generating circuit for generating high voltage pulses for starting the lamp. The pulse generating circuit is comprised of a step-up transformer, a start capacitor, a voltage sensitive bidirectional switch (e.g., a sidac) and an impedance which forms a charge circuit for the capacitor. The capacitor discharges via the switch and a part of the transformer to generate a high voltage pulse which is coupled to the lamp electrodes. An auxiliary capacitor and a serially connected inductor are coupled in parallel with the pulse generating circuit so as to clamp the open circuit voltage at a high level upon generation of the ignition pulse thereby to maintain a level of lamp current sufficient to sustain the discharge arc. This makes the lamp ignition more reliable and extends the lamp life.

Abstract: In a nuclear magnetic resonance apparatus the permanent magnetic material of the main magnet is formed by magnetized bars bounded by flat planes which surround a field space with a polygonal cross-section. Fitted around the permanent magnetic material is a return yoke of high-permeability material whose geometry can be matched to the locally prevailing flux. Extra magnetic devices can be fitted to improve the field uniformity in the field space enclosed by the magnetic material.

Abstract: A semiconductor device includes insulated gate field effect transistors, with which logic gate circuits having a satisfactory switching speed and a high packing density can be realized. The logic gate circuits are composed of transistor structures having a common source zone (22), which each comprise a gate (33), a second semiconductor zone (25) and one or more drain zones (28) and are manufactured in DMOS technology. The gates are strip-shaped or have at least a strip-shaped part. The gate circuits can be integrated in a simple manner with one or more high-voltage transistors manufactured in DMOS technology.

Abstract: Apparatus for addressing a character memory of a data display system in which displayed data is composed of discrete characters the shapes of which are determined by selected dots of a dot matrix. When character information conforms to different character modes of the form m.times.n.times.b, where m.times.n is a bit matrix format which is repeated b times to provide b-bits per displayed character dot, the stored character information includes mode bits which identify the mode. These mode bits are read out by logic control and addressing means by a first address and are used to determine a second address which varies according to the size of the mode and how many bit patterns it contains. The two addresses select all of the dot information required for the display of characters in real time.

Abstract: A magnetic field sensor includes a magnetic field-sensitive element (1), more specifically a magnetic field-sensitive multi-collector transistor (2). To reduce the offset, the setting of this element is modulated to vary the sensitivity. In the variation of the output signal of the element (1) in response to the variation in the sensitivity the offset has then been reduced.

Abstract: Apparatus for synchronizing the oscillators of several clocked direct voltage converters where each direct voltage converter has a control circuit with the oscillator as an integrated component and each control circuit has a connection for a capacitor and a connection for a resistor for defining the oscillator frequency. Commercial elements TDA 4714 and TDA 4716 are preferred as the control circuit. The synchronization is attained by adjusting the frequency of the oscillator of a first direct voltage converter to be higher than the frequency of the oscillators of the remaining direct voltage converters. A pulse sequence with an impulse frequency proportional to the oscillator frequency of the first direct voltage converter is transmitted by the first direct voltage converter to all of the other converters through an element that provides isolation between the different potentials. The pulses of the pulse sequence adjust a predetermined charging state for the capacitors of the other direct voltage converters.

Abstract: A switched-mode power supply circuit for converting a d.c. input voltage into a d.c. output voltage. The circuit includes a controllable power switch (Tr1) connected in series with the primary winding (L1) of a transformer (T). This winding forms part of a resonant circuit. To reduce the power losses caused by turning on the switch, the drive path of the switch incorporates a delay network (R11, C9) for each time delaying the turn-on until an instant which is substantially half a cycle of the resonance frequency later than the initial instant of the decrease of the voltage across the switch during its previous cut-off time.

Abstract: On a support which supports a light-emitting semiconductor device there is arranged a cap which is hermetically sealed to the support. In the cap there is provided a transparent plate, an inner layer of which facing the semiconductor device consists of a material having a high refractive index (>1.7). On the outer side of the plate there is provided a layer of photosensitive lacquer which is exposed to the light emitted by the semiconductor device. After development of the layer of lacquer, only the exposed part which is situated opposite the semiconductor device remains. This part is heated to the melting point, thus forming a droplet of lacquer, after which the outer layer of the plate and the droplet of lacquer are removed by way of a non-selective etching method, so that a lens which is situated opposite the semiconductor device and a flat window which surrounds the lens are automatically formed at the same time.

Abstract: A charge transfer device has a charge transfer channel and at least one second storage site situated outside this channel, whereby a connection channel for transferring charge packets is present between a first storage site situated in the charge transfer channel and the second storage site, which connection channel can be controlled by a transfer electrode. The transfer electrode is strip-shaped and extends in the longitudinal direction of the charge transfer channel. According to the invention, the transfer electrode essentially lies beside the charge transfer channel and has at the area of an end of the connection channel a projection which ensures satisfactory charge transfer from the storage site to the connection channel.

Abstract: The invention proposes a method and a device in which resonance signals (generated for NMR imaging) are sampled in the presence of a static or semi-static and time modulated gradient magnetic field with the gradient direction of the fields applied being mutually perpendicular. The resonance signals are conditioned prior to the start of sampling. The sampled signals are associated with spatial frequencies (i.e. points in a spatial frequency space (k.sub.x, k.sub.y) which is the (2-D) Fourier transform of the actual (s, y) space), which are determined by the applied gradient fields. The static or semi-static gradient field always produces an increase (for example, in k.sub.x), while the time modulated gradient field always produces an image frequency which lies between two limits (k.sub.y and k.sub.y +k.sub.y). Consequently, the invention enables determination of NMR spectroscopy data in an entire band in the (k.sub.x, k.sub.y) space.

Abstract: In an adaptive electronic buffer system in which a set circuit generates logic set signals for the buffer circuits, parallel sub-buffers are switched on or off by the set signals, so that the specified charging and discharging times of the output can be achieved. This setting compensates for the manufacturing process variations and operating conditions (temperature, supply voltage) of the buffer circuits. The spread in the output conductance is reduced, thus reducing the risk of fast current variations, inductive voltage peaks and the associated loss of data.

Abstract: A first resistor (R.sub.1) and a first capacitor (C.sub.1) constitute a filter arrangement having a time constant which is not very accurate due to the inaccuracy of the resistor and the capacitor values in integrated circuits. The time constant is adjusted using a circuit comprising a reference resistor (R.sub.2) and a switched capacitor (C.sub.3). The value of the reference resistor (R.sub.2) and the equivalent resistance of the switched capacitor (C.sub.3) are compared by means of an integrator (C.sub.2, 2) from whose output (9) a control voltage is taken via a hold circuit (C.sub.4, C.sub.5). The control voltage is equal to the voltage at that point on the reference resistor where the resistance value is equal to that of the switched capacitor (C.sub.3). By means of comparators (21 to 30) and switches (S.sub.11 to S.sub.20) a percentage of the total resitance of the first resistor (R.sub.1) is short-circuited. This percentage is equal to the difference between the resistance of the reference resistor (R.

Abstract: In a nuclear magnetic resonance apparatus, a loudspeaker element free of magnetic material acts as an acoustic reproduction element. The loudspeaker element is arranged in the magnet space so that the main field of the magnet acts to generate a Lorentz driving force for the element. Together with a microphone function or an additional microphone (50) and an external loudspeaker.microphone system, a two-way acoustic communication system can thus be formed. Such a loudspeaker element free from magnetic material does not produce field disturbances in the magnet.

Abstract: An assembly of a whisker disc and pan on a mounting element for quickly mounting the disc and pan on a wire pay out tree.

Abstract: A high pressure discharge lamp with a multi-bent wire frame which provides symmetrical orientation and improved structural support for a pair of discharge devices which are supported at their tops by an element which allows for differential expansion of the devices.

Abstract: A device for generating the audio information of a set of characters in which some characters are intoned or pronounced with a different voice character. The device includes means for making a distinction between a capital letter and a small letter presented. For a capital letter character, a speech pattern is formed in which the pitch or the voice character is modified, while maintaining their identity, with respect to a speech pattern for a small letter of the same character. The device also includes means for determining the position of a letter, preferably the last letter, of a word composed of characters presented and for forming a speech pattern for the relevant letter in which the pitch or the voice character is modified while the identity is maintained.