| 摘要 |
953,809. Pulse generating circuits. SOC. DE PROSPECTION ELECTRIQUE SCHLUMBERGER. May 17, 1962 [May 19, 1961], No. 19125/62. Headings H3P and H3T. A circuit for generating a single cycle of sinusoidal oscillation each time a trigger pulse is received comprises a series-tuned circuit 1, 2 charged from a D.C. supply 8 via a switching device 11 and discharged via a second switching device 4 having a diode 7 connected in parallel opposition. The devices 4, 11 may be vacuum valves, transistors, thyratrons or equivalent semi-conductor devices. In Fig. 2, capacitor 1 is initially charged slowly via a trigger circuit 13 and inductor 2, a delayed-switching device 33 being provided to ensure that the pulse generator 6 is inoperative until the capacitor 1 is initially charged. Each pulse from generator 6 is lengthened at 34 and drives transistor 4 into conduction, discharging capacitor 1 resonantly via a load 3 and inductor 2. The negative halfcycle of discharged current passes via diode 7. At the end of each discharge cycle, the voltage at 15 causes a circuit 13 to trigger transistor 11 rapidly recharging capacitor 1 via inductor 9. In Fig. 3, capacitor 1 is initially charged via resistor 23 and inductor 2. When capacitor 1 is charged to the value of a reference voltage from source 24, the output from a voltage comparator 25 opens an AND gate 28 to allow trigger pulses from source 6 to reach the thyratron type semi-conductor 4 which provides a resonant discharge of capacitor 1 via inductor 2 and load 22, connected via a current transformer 21. At the end of each discharge cycle, the voltage at 15 is sufficient to cause a circuit 13 to trigger the thyratron type semi-conductor 11 which recharges capacitor 1 via inductor 2. |
