GB737954A - Improvements in or relating to an electric apparatus in which the electron beam of one or more trochotrons is intended to be directed in synchronism with the stepping velocity of the electron beam of a controlling trochotron or in synchronism with a multiple of said stepping velocity - Google Patents

Abstract

737,954. Thermionic distributers. TELEFONAKTIEBOLAGET L. M. ERICSSON. July 14, 1953 [July 18, 1952], No. 19575/53. Class 40 (3). The invention relates to trochotron electrondischarge tubes of the type described in Specifications 675,465 and 709,264 and concerns an arrangement for directing the beam of one or more trochotrons in synchronism with the stepping velocity or a multiple thereof of the electron beam of a controlling trochotron. According to the invention, and as illustrated in Fig. 1, the control electrodes 11-14 of the controlling trochotron 1 are connected to the corresponding control electrodes 11<SP>1</SP>-14<SP>1</SP> of a controlled trochotron, such as 2. The controlling trochotron is stepped by any known method, such as by applying negative pulses at 19 to the commoned contact electrodes 7-10. When current reaches a control electrode, a voltage drop occurs across the associated resistor 15-18 and thereby decreases the potential of the corresponding electrode in the controlled trochotron causing the beam to be stepped similarly. The arrangement leaves the contact electrodes 7<SP>1</SP>-10<SP>1</SP> of the controlled trochotron free and they may be employed to supply gate pulses to devices connected to them, such as pulse modulators and demodulators. Since the potentials for the control electrodes are derived from outside the tube, the cathode current of the controlled trochotron need not be continuous but may be pulsed. Condensers are preferably shunted across resistors 15-18 to render the operation of trochotron 1 more reliable. Several trochotrons are controlled from one by parallel connections. Reference is made to the use of coaxial trochotrons with the resistors 15-18 in Fig. 1 replaced by parallel resonant circuits. To cause a controlled trochotron to stop at a multiple M of the controlling' trochotron frequency f, the corresponding control electrodes, e.g. 3, 13<SP>1</SP>, are connected together by a circuit as shown in Fig. 2 in which 21 comprises a diode and 23 a resonant circuit tuned to the desired multiple of the stopping frequency. Current pulses from the control electrode 13 supply energy to the circuit 23 every Mth cycle, and during the other cycles the oscillations are maintained by energy stored in the circuit. Phase-shifted sinusoidal voltages thus appear at the control electrodes of the controlled trochotron and cause the beam to be stopped at the frequency Mf. If the cathode current of the controlled trochotron is continuous energy is supplied to the tuned circuit and the trochotron becomes mainly freerunning with synchronizing energy supplied each Mth cycle.