Patent GB-590260-A (GB)
Title: Deflection arrangements for oscillographs
IPC: H03K4/26
Filed: 1945-04-14
Abstract: 590,260. Cathode-ray oscillographs. STANDARD TELEPHONES & CABLES, Ltd., and CLEAVER, R. F. April 14, 1945, No. 9384. [Class 37] An arrangement for producing a line trace on the screen of an oscillograph, the length and position of which trace are determined by the magnitudes of steady electric control currents or voltages applied to the arrangement, comprises reactive elements associated with the deflecting elements of the oscillograph and periodic means for alternately storing and discharing energy therein, resistances being associated with the reactive elements during the storing and discharging. As shown in Fig. 1, the deflecting plates 1, 2, 3, 4 of a cathode-ray oscillograph are supplied with steady deflecting potentials from terminals 5, 6, 7, 8 through resistances 9, 10, 11, 12. The plates are connected to a common potential terminal 21 by condensers 13, 14, 15, 16 provided with discharging resistances 17, 18; 19, 20 which are simultaneously shunted across the condensers by a switch 22. If the resistances 9 . . . 12 are equal, the resistances 17 ... 20 are equal, and the condensers 13 . . . 16 are of equal capacitance, the spot on the oscillograph screen follows a straight line during each charging period. In a practical form of this arrangement, Fig. 3, the switch 22 is composed of four triode valves 23, 24, 25, 26, the cathodes of which are connected to the terminals 21 and the anodes to the upper terminals of the condensers 13, 14, 15, 16. The control grids are all connected to a terminal 27, between which, and the cathode terminal 28 is applied an alternating switching voltage for alternately blocking and unblocking the valves. Two pairs of voltages are developed in a direction indicating circuit and are applied to the terminals 5, 6 and 7, 8. In order that all these voltages shall be positive, a negative biassing voltage greater than the maximum voltage to earth of any of the terminals 5 ... 8 is applied to the terminal 21 from a source 29. A radial trace is then obtained on the screen oriented in accordance with the values of the pairs of balanced voltages and therefore giving the desired direction indication. Each of the condensers 13 . . 16 may alternatively be connected in parallel with the corresponding resistance 9 . . . 12 instead of to the common terminal 21. Each of the condensers may be replaced by an inductance. In a modification, Fig. 4, a condenser 31 is connected between the plates 1, 2 and a similar condenser 32 between the plates 3, 4. Two discharging resistances 33, 34 are periodically connected across the condensers by a switch 35, which may consist of one or more relays operated by alternating or intermittent current and controlling simultaneously the necessary sets of contacts. In the arrangement shown in Fig. 7, electromagnetic deflecting coils 55, 56, 57, 58 are employed in the oscillograph. One pair of coils 55, 56 are connected in series with resistances 9, 10, the other pair 57, 58 being connected in series with resistances 11, 12. The resistances 9 . . . 12 are placed between the condensers 31, 32 and the corresponding deflecting coils.