Abstract: A damping material (19) is provided on one of the two side faces (7, 8), of a magnetic head having two plate shaped ferrite core limbs (3, 4). The material consists of a synthetic resin filled with less than 30% by volume of filler having a density of more than 10.times.10.sup.3 kg/m.sup.3. The filler is at least 74% by weight of the damping material and the density of the damping material is larger than 4.times.10.sup.3 kg/m.sup.3 and its modulus of elasticity ranges between 10.sup.7 and 10.sup.9 Pa.

Abstract: A rotatable magnetic head assembly for use in a magnetic tape recording/play-back device of the helical scanning type, the assembly comprising two diametrically oppositely located magnetic transducing heads (12, 12'). In order to enable recording of a number of tracks simultaneously without the use of a protective band, the heads (12, 12') are constructed and aligned relative to other so that they each form two oblique tracks (38A, 38B) on a magnetic tape (6) and a given intermediate space. At least one track (39A) is formed in the intermediate space by the other head.

Abstract: The display arrangement is provided with display elements which comprise a first and a second electrode, between which each a displaceable third electrode is present, and with a control voltage source, for selectively situating the third electrode near the first or second electrode, depending upon a voltage difference with the first or second electrode. In order to obtain a minimum or no cross-talk from selected display elements to adjacent selected or non-selected display elements, the display elements being arranged in a matrix in rows and columns, the voltage source supplies at least during the period (DT) of the information supply to the display elements (R1C1, R1C2, . . . R3C3) three values of control voltage (SC1, SC2, SC3) to at least one of the three electrodes.

Abstract: Control circuit for memory type matrix display with k columns and r rows for k times r display elements, wherein each display element can have one of 2.sup.m brightness levels. This control circuit has a video memory for storing brightness information for the display element of each column. It comprises a column memory for each column. Each column memory including m column shift registers. Each column shift register having an input coupled to a corresponding information input for that column, and an output. A line time shift signal C.sub.s being applied to the shift pulse input of all column shift registers for shifting all column shift registers substantially at the end of each line time. The m output bits thus obtained are sequenced by means of a controlled gate circuit to produce a sequence of output bits at the information output of that column. This gate circuit is controlled such that each output bit lasts a predetermined part of the subsequent video line time.

Abstract: For the display of a phenomenon or a small number of phenomena by means of an oscilloscope comprising a liquid crystal display screen, a simple matrix excitation circuit is described wherein a time-division multiplex excitation with a great number of lines and a good contrast appears possible if for each column only one or a few picture elements must be set to the ON-state, costly provisions such as voltage and temperature stabilization being required.

Abstract: A modulator circuit for a matrix display device, the modulator circuit having pulse width and pulse amplitude control. The current amplitude for a selected picture element (row address-column address) varies during the pulse width of an excitation pulse in correspondence with the number of counting positions of a counting circuit used for determining the pulse width.A column conductor has an associated column excitation circuit in which a counting circuit for determining the excitation pulse width controls excitation switches which pass selectively currents from current source I.sub.A . . . 64I.sub.A of a current source circuit to the column conductor. The initial setting of the counting circuit determines the excitation pulse width, and the count positions of the counting circuit select the currents to be passed to the column conductor as the counting circuit is stepped by clock pulses to measure the duration of the excitation pulse.

Abstract: In a display device having a liquid crystal the gate circuits for the row selection switches (25, 26) can be considerably simplified by coupling a terminal (30) of the supply source (32) for the selection switches to the ground conductor (39) by means of an auxiliary supply source producing a periodical pulsating direct current voltage (33, 34, 40).To simplify the drive of column excitation switches (26, 28) a further auxiliary supply source (43, 44, 50) can be used in a similar manner for a display device which drives liquid crystal display elements (1, 2, 3, 4) of the rms-type in time-division multiplex.All the required voltages can be obtained from one central supply source (122, 124) by means of at least one current source circuit (100, 102).

Abstract: In a matrix of display elements arranged in rows and columns having row scanning and column selection, all display elements which are connected to a scanned row conductor are always ignited such that the non-selected display elements of that row receive a low quiescent current through quiescent current supply circuits in the column selection circuits and the selected display elements receive a higher display current through selection circuits in the column selection circuits.The low quiescent currents reduce the ignition-voltage required for the next following row to be scanned while a high contrast is produced between the selected and non-selected display elements.