GB880525A - Improvements relating to pulse generators - Google Patents

Abstract

880,525. Pulse generator circuits. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. Feb. 5, 1959 [Dec. 20, 1957], No. 39668/57. Class 40(6). [Also in Group XL(b)] In a pulse generator of the type described in Specification 589,127 in which the load across which a pulse is to be generated is connected between a pair of normally charged delay circuits and in which the pulse is initiated by shorting the far end of one line where one of the conductors of each of the lines are connected together this conductor of the other line is given a high impedance between its ends by linking a magnetic core with the line. Fig. 4 shows a pulse generator in which two delay lines DLI, 2, are charged from a source (not shown) and are connected to a load, for example a magnetron oscillator, so that when a switch S, for example a gas discharge tube is closed, the end of the line DL1 is shorted, a negative pulse thus travels along this line to the load, passes back along lines DL1, 2 being reflected with inverted polarity from line DL1 and with the same polarity from the end of line DL2. Thus the reflected pulses cancel out at the load and a pulse of duration 2T, where T is the one-way transit time of each line, is generated a period T after the closure of switch S as shown in Fig. 2. In order to prevent the load from being short circuited at high frequencies along the outer conductor of line DL2, a magnetic core H1 is linked with the line thus isolating the points BD for the duration of the pulse by forming a high impedance between its two ends. In the modification shown in Fig. 5 the output of the two circuits of the kind described in Fig. 4 are connected in series so that the pulses which are initiated by simultaneously closing switches S, S1 will be additive across the load. Since the outer conductors of lines DL1<SP>1</SP> and DL2 are interconnected electrically throughout their length a large magnetic core H3 links with both of the lines and at the same time the two ends of the outer conductor of line DL2<SP>1</SP> are separated by the high impedance of core H2. In a further modification, Fig. 3 (not shown), the core H2 is replaced by two cores separated along the conductor and a point between them is coupled to the outer conductor of lines DL1<SP>1</SP>. Fig. 7 shows a modification in which the left part of line DL2<SP>1</SP> is threaded through a large core H6. Various types of D.C. charging circuits are described with reference to Fig. 8, Fig. 9 (not shown), in which an H.T. supply via combinations of chokes and rectifiers are used. Fig. 10 shows an arrangement in which lumped characteristics may be employed in place of the concentric cable, two sections of lines AL1, 2 are linked at the centre by a few turns which are themselves linked with the magnetic core H. Specification 839,854 also is referred to.