Pulse testing techniques have been used for many purposes for a long time. In studies of waveguides as radio and radar components and for possible communications systems use, we have employed various types of pulse testing. The need for greater resolution through the use of very short pulses has always been apparent. For this reason, equipment has recently been built to generate and display 9,000 megacycle pulses having a length of about 6 millimicroseconds. In a pulse of this length there are less than 100 cycles of radio frequency energy, and the pulse occupies less than 10 feet of path length in the transmission medium. The r-f bandwidth required is about 500 megacycles.