Sferic signal simulator is used to produce an impulse  signal which simulates the waveform of a sferic, a radio atmospheric signals produced by a lightning strike. In time domain, the waveform of a sferic signal is a single high amplitude spike. When this pulse is analyzed in frequency domain, it will show a wide band spectrum ranging from few kilohertz to several tens of kilohertz. Here is the schematic diagram of the sferic signal simulator circuit:

Sferic Simulator Circuit circuit schematic

This small and lightweight circuit will be useful for testing many telecommunication devices before operated in the real environment with real sferic disturbances. The input of this circuit receive a square wave  pulse with  fast rise and fall times, 100 ns or faster which will produce the desired output waveform. Limit the repetition rate of the input pulse below 3000 pulse per second to ensure the perfection of the emulated sferic signal waveform at the output.