Abstract: A chopped power supply converter is provided comprising, between the two terminals of a DC power supply source, on the one hand a primary inductance (L.sub.p) in series with a chopping means (Tr) and on the other hand a capacitive divider bridge formed by two capacitors (C.sub.1 -C.sub.2), a secondary inductance (L.sub.s) coupled to the primary inductance (L.sub.p) and whose value with respect to this latter depends on the ratio of the capacitive divider bridge (C.sub.1 -C.sub.2), this secondary inductance (L.sub.s) being connected between the output terminal of the divider bridge and the load (P) through a series diode (D.sub.1) and a parallel capacitor (C.sub.3), and a balancing device (E) for permanently rebalancing said divider bridge.

Abstract: A process for eliminating the disturbances related to fluctuations of the load in chopped power supplies comprising a magnetic circuit with a primary inductance (Lp) coupled to a secondary inductance (Ls), characterized in that it consists in automatically adapting the value of the secondary inductance (Ls) as a function of the voltage (Us) at the terminals of the load (X), so as to ensure total transfer of the magnetic energy for each period of the chopping frequency.

Abstract: A railway track comprising a pair of rails is divided into a succession of segments, each segment having a railway track circuit for separating successive trains. The track circuit is switchable between an initial state and a complementary state and comprises a downstream impedance electrically connecting the rails at a downstream point, an upstream impedance electrically connecting the rails at an upstream point, an electromagnetic sensor located between the upstream and downstream impedances in the vicinity of one of the rails, a transmitting member, and a pair of receiving members. One receiving member is in electromagnetic communication with the electromagnetic sensor. The transmitting member and the other receiving member are switchable between connection to the downstream impedance and the upstream impedance.

Abstract: An electronic drive system for a discharge lamp is disclosed wherein the switching frequency of the chopper is reduced until the lamp striking voltage has reached about 70% of its rated value. The system includes a chopper transistor, a control for varying the transistors duty cycle and a smoothing inductance, freewheeling diode and smoothing inductor to smooth the chopper output. Current limiting is provided to prevent overcurrent within the chopper transistor, smoothing inductor or lamp.

Abstract: A process for coding track circuits allows particularly information to be transmitted to a vehicle travelling over a railway track divided into a succession of sections each equipped with a track circuit, in which each of the carrier frequencies for energizing the track circuits is frequency modulated by means of a number of modulation frequencies each representing a piece of information to be transmitted. This process includes the steps of comparing the modulation frequency obtained by demodulation of the modulated carrier frequency with another source of modulation so as to check that said modulation frequency is indeed correct, and to allow transmission of the modulated carrier frequency in the corresponding track circuit only when this check is positive. This process and device applies to high-speed railway trains.

Abstract: An electrical joint for separating adjacent block circuits of a railway signaling system in which the rails of the railway track serve as conductors. The upstream circuit block carries first frequency signals and the downstream block circuit carries second frequency signals. The electrical block separating joints are bounded by tuning units of which one may be a mere impedance and which are responsive to the frequencies of the circuit blocks and constitute respectively a low impedance for the first or second frequency and a capacitive impedance for the other of the first or second frequency. There are transmitter and receiver units the latter of which is associated to activate a control device, e.g. a relay, for the associated block circuit to de-activate the control device when a vehicle enters the electrical joint by a shunting effect.

Abstract: An inductive energy transmission device for firing an igniter which has primary and secondary windings and a fixed magnetic screen designed to be generated by the primary winding.