The use of pre-pulse techniques in high-speed oscillography

The recording of single transients of very short rise time and duration has necessitated the development of ultra-high-speed oscilloscopes. It is shown how the high-frequency range of conventional oscilloscopes and associated amplifiers can be extended by switching them into operating conditions of high current for only a very short part of the duty cycle. An amplifier is described which has a gain of 360, an output of 200V and bandwidth 140 Mc/s at ¿3 db; using only four amplifying valves. Pre-pulsed time-bases are discussed, covering the range 5 to 250 m¿sec, and a high-speed pulse generator is described which may be used for testing pre-pulsed oscilloscopes.