Abstract: An apparatus for recording and/or reproducing signals on a magnetic tape, having an azimuth adjustment for the gap of the magnetic head. At least one fixed support on a head plate has a slotted opening for receiving the free end of a tab on the head support, to form a knife-edge bearing about which the head and support are pivoted. A tape guide is formed on the head support immediately adjacent the tab.

Abstract: The invention relates to an electronic flashgun comprising an arithmetic unit (9) for computing a diaphragm stop number-distance combination, the arithmetic unit comprising a transparent element (11) with a pointer (10). This element is connected to a neutral density filter disc (21) having a variable density and located in front of a light cell (6) provided at the light exit side of the flashgun. The pointer directly indicates a diaphragm stop number on a diaphragm stop number scale (13) of the arithmetic unit.

Abstract: A shock-proof gas discharge laser device comprises a cylindrical discharge vessel secured coaxially in a metal tubular holder. The cylindrical discharge vessel is sealed at its two ends with sealed metal end plates provided with supports for multilayer reflectors. The metal end plates are centered in beaker-shaped insulator caps which surround the end plates. The cylinder surface of the caps extend at least partly within the metal tubular holder in contact therewith. The electrical connections of the gas discharge laser are provided in said caps.

Abstract: The invention relates to a discharge lamp which has a discharge vessel provided with an external auxiliary electrode. The lamp also has a bimetal which in the inoperative condition of the lamp causes the external auxiliary electrode to bear against the discharge vessel. According to the invention the auxiliary electrode is connected to an end of only one bimetallic strip and in the operating condition of the lamp the auxiliary electrode is remote for the greater part from the discharge vessel due to the action of the bimetal. Combined with an operating condition of the lamp in which no hindrance is experienced from the auxiliary electrode.

Abstract: A coupling element for an optical transmission system, in which the coupling element comprises a convex lens having a refractive index which is dependent on the radius r of a shell in the lens, and a holder. Use is preferably made of lenses having a refractive index N.sub.(r) =N.sub.1 .multidot.(2-(R/Ro).sup.2)1/2, where N.sub.1 is the refractive index of the core of an optical fiber (approximately 1.55) and Ro is the radius of the lens.The coupling of monomode fibers via lenses of this kind can be effected wth large dimensional tolerances.

Abstract: A method of making a master replicating tool having a predetermined negative aspherical profile from which aspherical profiled optical elements can be made, comprising machining a blank of a hard, non deformable siliceous material with a cutting tool in a one stage machining operation to produce substantially the predetermined profile, coating the surface so produced with a layer of nickel or nickel based alloy, machining the nickel or nickel based alloy to produce the predetermined profile with the cutting tool and protecting the surface by applying a layer of an inert, scratch-resistant material thereon. Hand figuring the blank after machining is avoided. The scratch-resistant layer is thin and can be between 500 A and 5000 A thick. This layer is applied by vapour deposition and is preferably vacuum deposited vitreous carbon.

Abstract: A impedance matching window for an ultrasound transducer comprises a periodic array of stepped structures. Each stepped structure comprises a plurality of parallel matching strips disposed side-by-side on an active surface of a piezoelectric ceramic.

Abstract: A bandstop filter for very high frequency transmission lines having distributed constants, having several filtering elements each intended to prevent the transmission of a specific frequency band. The first filtering element is a quarter-wave filter, the second element an assembly of two transmission paths of a length such that the signals present at the outputs have opposite phases and cancel other, the third element being a quarter-wave filter, these elements being grouped such that they form an extremely compact filter which is little sensitive to proximity effects.

Abstract: An encoding circuit for a SECAM color television transmitter having a frequency modulator circuit for a modulating signal which comprises two color difference signals which follow one another line-sequentially and are controlled by means of two phase control loops and two reference signal generators. A first reference signal generator has one of the reference frequencies whereas the frequency of the signal generated by the second reference signal generator is a harmonic of the line frequency. The phase control loop to which the second reference signal generator is connected comprises a sample and hold circuit which is operative at field frequency.

Abstract: A stepping motor having a first and a coaxially disposed second annular stator section, which stator sections are axially spaced by a coaxially disposed permanent-magnetic ring. Each stator section terminates on the inner side in two coaxially disposed annular systems of teeth. The systems of teeth of each stator section have been mutually shifted nominally by 1/2 tooth pitch relative to the rotor toothing and the systems of teeth situated on the outer side relative to the permanent-magnetic ring as well as the systems of teeth situated on the inner side relative to the permanent-magnetic ring exhibit a mutual shift relative to the rotor toothing of nominal 1/4 tooth pitch.

Abstract: A device for recognizing overall patterns of digital signals which are arranged according to at least one coordinate comprises: first storage means for the storage of a pattern to be presented for comparison; a window device for selecting a local pattern of a number of digital signals from the overall pattern; a stepping mechanism for coordinate-wise adjustment of the window device over a step; a gradient determining device for determining, for predetermined coordinate values within the window, the absolute value of the coordinate-wide gradient of the values of the digital signals prevailing at said coordinate values; a moment generator for receiving these absolute values, for determining the moment therefrom with respect to a focussing point of the window, and for generating an output signal when a predetermined minimum value of said moment is reached in order to indicate the reaching of a local maximum in said coordinate-wise gradient; second storage means for the storage of a number of reference patterns;

Abstract: An electronic transmitter for direct current telegraphy systems. In order to limit cross-talk between neighboring telegraph lines it is known to filter telegraph signals prior to transmission to "round-off" their edges. In the present electronic transmitter telegraph signals are given approximately "sinusoidal edges" by the use of a function generator. In FIG. 1 an electronic transmitter comprises an input circuit 1, a switching circuit 2 and an output circuit 3. Binary information signals at an input produce telegraph signals on a telegraph line 6-6'. The output circuit 3 comprises two function generators 15 and 17 and a current source 21. Switches 11 and 14 in the switching circuit 2 control which function generator is operative in response to command signals D.sub.1 and D.sub.2 from the input circuit. The result is that current pulses from the current source 21 have exponentially varying leading and trailing edges which approximate the sinusoidal edges as shown in FIG. 2.

Abstract: A threshold arrangement includes two complementary transistors whose channels are situated in series between two supply terminals. In order to obtain a substantially square-wave relationship between the output voltage on the common drain electrodes and the input voltage on the interconnected gate electrodes, a direct voltage source is included between the two gate electrodes, which source has a voltage which is preferable substantially equal to the supply voltage minus the sum of the threshold voltages of the two complementary transistors.

Abstract: A method is provided for positioning a supporting frame for a color television tube mask in a repeatedly obtainable rest position with respect to the face plate of the tube during various stages of the tube manufacture which require accurate positioning of the frame. Such stages include attachment of the mask to the frame to form a color selection electrode, connection to the frame of means for increasing the mechanical stability of the electrode, and repeated exposures and chemical treatments of color phosphors on the face plate. The method comprises applying a time-varying magnetic field to the frame until it is vibrated into an ultimate rest position relative to the face plate.

Abstract: A transformer comprising two C-shaped core parts arranged to form a core ring with one or more coil formers which are molded on one core leg or on both oppositely situated core legs, the core ring being interrupted between the moulded coil formers.

Abstract: Disclosed is an apparatus for reproducing digitally coded information recorded on a disc-shaped record carrier in the form of optically detectable, unit information areas arranged in accordance with a concentric or spiral track pattern. The apparatus comprises a filter which is tuned to a frequency f=V/L, V being the nominal tangential speed of the record carrier and L the nominal center-to-center distance of said unit areas. This frequency component has a frequency equal to twice the bit frequency of the coded information and is situated at a zero point of the power spectrum of said information, so that the extracted signal may be employed for the generation of a clock signal.

Abstract: A radiation-sensitive semiconductor device includes a radiation-detecting avalanche diode which has a semiconductor layer structure made up of four layers of the same type conductivity. The fourth semiconductor layer is located above the third layer and has a higher doping concentration than that of the third layer. This fourth layer substantially improves the noise properties of the device, by a factor of about 2. The radiation-sensitive semiconductor device is manufactured by a method in which the first and third layers of the semiconductor layer structure are provided by epitaxial growth, while the second and fourth layers of the structure are provided by ion implantation. The structure and method of the invention are particularly useful in the manufacture of avalanche photodiodes with an improved noise factor.

Abstract: A gas discharge laser comprising a glass cylindrical discharge vessel having at least one end sealed by means of a metal cap provided at its center with a reflector body and in which a metal exhaust tube is connected eccentrically to the cap. By forming the metal cap in the shape of a truncated cone and providing the metal exhaust tube in the conical surface therof, a gas discharge laser having a high degree of directional stability is obtained.

Abstract: A device for providing closed ring cores with windings. A coil former is rotatably arranged on at least one core leg. Between the coil former and the leg there is provided a guide member which is secured to the leg and which comprises guide paths for the coil former rotatably arranged thereon. The coil former is fixed in position after a coil is wound thereon.