Abstract: A scintillation camera has photomultipliers and a number of auxiliary radioisotope sources to calibrate the photomultipliers. The calibration circuits can be either analogue or digital.

Abstract: This transition detector is intended to supply pulses which characterize the instants the signal passes a threshold. This signal, which appears in a rectangular form is applied to a first integrator which supplies a signal which increases or decreases in accordance with the sense of the rectangular signal and to a branch which comprises a series arrangement of a delay circuit and a second integrator which is identical to the first. The outputs of the two integrators are connected to a comparator which supplies the desired pulses. At least at the start, the output of the first integrator is entered in a store at a given instant and at an instant which is so much later as the delay supplied by the delay circuit the second integrator is forced to assume the value stored in the store.

Abstract: A deflection coil consisting of a number of elementary coils formed by folding flat coils along four folding lines such that at the area of the folding lines each turn crosses all other turns. Very accurate deflection coils can thus be manufactured in a simple manner.

Abstract: A circuit is shown for compensating for rapid changes in D.C. levels in high pass filter coupled vertical deflection circuits. It features a second high pass filter that applies a D.C. signal having a second level change so that the first change is cancelled out. The second change can be applied directly to the first change with opposite polarity, or to the emitter of a transistor that receives the first change at its base with the same polarity.

Abstract: An electronic switch for use in television which is provided with a master-slave flip-flop which comprises a trigger input for supplying a switching signal which occurs at the field frequency and which has a switching pulse edge which occurs in field blanking times and with a condition input to which a capacitor-charging-discharging circuit is connected which circuit comprises a push-button switch which has one stable state only.

Abstract: A chopper blade has parallel edges and is rotatably mounted on two eccentric discs. As one disc is driven, the blade moves across an optical beam in parallel fashion. Elliptical drive gears can be used to achieve linear speed.

Abstract: A receiver tuning circuit in which without operation of extra switches a change-over can be made from tuning by means of a continuously varying tuning voltage to tuning by means of one of a number of adjusted tuning voltages by using a capacitor controlled by an automatic tuning correction current source circuit for obtaining said voltage, and an automatic switch for applying the desired tuning voltages to this capacitor.

Abstract: A high gain digital phase comparator which in digital phase lock loop systems can give a thousand-fold reduction in ripple and close-in noise sideband amplitudes. The comparator is of the sample-and-hold type but the normal ramp reference waveform is replaced by a trapezoidal waveform with a very steep rising or falling slope generated by a trapezoidal waveform generator. This slope is sampled by a sampling circuit coupled to said generator and its steepness gives the increased gain of the phase comparator leading to the reduced noise and ripple. Additional logic and switching circuits are added to make the comparator operate only during a rising edge of the trapezoidal waveform.

Abstract: A double walled smoke stack is made up of stackable sections. The top part of each section has a member extending between inner and outer shells and is either downwardly prestressed towards the inner shell or is flexible. This allows the inner shell to upwardly expand.

Abstract: A deflection coil unit for color television, comprising coils which are toroidally wound on a ring core having a flared inner surface. The parts of the coils which extends along the inner surface are situated in grooves having side walls whose plane is parallel to the axis of the ring core.

Abstract: A generator suitable for producing a sawtooth and a parabolic signal for the line or field deflection in a television system. The generator is provided with two dc coupled, series-connected difference amplifiers with feedback, which are each part of an associated integrating circuit. Via a peak detection circuit the output of the second difference amplifier is connected to the non-inverting input of the first difference amplifier. The second integrating circuit has been rated in such a way that the peak-peak value of the parabolic signal is half that of the sawtooth signal, while independent of the peak-peak value adjustment the ground potential is present in both signals in the center of trace; consequently there are no centering difficulties.

Abstract: A time video registration arrangement in which, with the use of a television camera, a storage device and a display device, each constructed in accordance with a television standard, time measurements can be performed at intervals smaller than the standard field period. To that end the arrangement is provided with a signal generator for supplying a field synchronization-deflection signal to the camera, which signal has a repetition period which is an integral part of the field period, while a video signal of standard field frequency is applied to the storage device.

Abstract: A receiver employs automatic wave-range switching. The wave-range information is used to have a station finding circuit run through the unwanted wave-ranges at a fast rate and run through the desired wave-range at a comparatively slow rate. This is done by applyng counting pulses having a switchable frequency to a counter governing the finding action.

Abstract: A deflection coil unit for color television display tubes in which the narrow end of a flared deflection yoke is mounted in a ball joint, adjusting means being provided at the widest end of the yoke for tilting the deflection yoke about a horizontal and a vertical axis through the ball joint. Thus, the convergence on the vertical and horizontal axis of the display screen can be adjusted. For the adjustment of the color purity, the ball joint is mounted such that it is axially displaceable in a housing.

Abstract: A black-white or color television camera has a pick-up tube having a signal electrode comprising separate strips. Before a line scanning operation to be performed by an electron beam takes place, the signal electrode strips are coupled to a reference potential. After the line scan, the strips which are coupled separately to parallel inputs of a switching circuit which is provided with switches coupled to the parallel inputs, are coupled for supplying video information. This results in a separation between electron beam scanning and picture signal supply by the pick-up tube, which has the advantage that the beam scanning does not affect the picture quality in the direction of line scan. Furthermore, the construction with strips yield an improved signal-to-noise ratio. The switching circuit may, possibly together with a shift register, be integrated in a semiconductor body, which is provided near the signal electrode in the pick-up tube or outside the pick-tube.

Abstract: A television system comprising a video tape recorder or the like and a television receiver, in which system the television signal contains an identification signal by which it is distinguished from the television signal received from a transmitter. The television receiver includes a circuit arrangement for recognizing the identification signal and for changing over circuits in the receiver, in particular for changing over the time constant network of the flywheel filter of the line synchronizing circuit. The identification signal can encode the line synchronizing pulses, for example by a serration formed therein.

Abstract: A chroma keying signal generator which does not operate in the usual manner with luminance dependent color difference signals (R-Y) and (B-Y) but with luminance independent chromaticity signals (R-Y)/Y and (B-Y)/Y. On the one hand a signal division may follow in the generator for deriving the chromaticity signals and on the other hand a threshold circuit may be used having a threshold voltage which varies with the luminance. Owing to the fact that generating the signal is independent of the luminance an intense, uniform background illumination without shadows thereon is no longer required.

Abstract: A color television camera having at least two pick-up tubes while the electromagnetic deflection and the electrostatic focussing is done in spatially removed places. A voltage source for supplying the anodes of the pick-up tubes is not stabilized but by affecting the deflection, registration of the line raster is maintained for voltage variations. Control of the voltage source offers the possibility for electronic "zooming" of the scene to be recorded.

Abstract: In a digital transmission for low bit rate transfer of speech signals, the frequency information content of the speech signal is transferred via a first transmitter channel and the amplitude information content is transferred via a second transmitter channel. A particularly low bit rate of 4.8 to 7 kbits/second is made possible in that the transmission device in the first transmitter channel is in the form of a uniform delta modulator which is provided with an input circuit which so changes the shape of the speech signal that the input signal to the delta modulator has a constant slope.

Abstract: A circuit for continuously recalibrating a gamma camera having a plurality of photomultipliers and signal channels which are weighted to control X and Y deflection on the display. Variation in signal channel gain is controlled and cancelled.