Pulse-width-modulated plasma sound source

A prototype of pulse-width-modulated plasma sound source with four independent outputs has been designed and tested, in which the main circuit includes a switched DC source for realizing effective capacitor charging and four independent discharging units for pulse forming. Each two outputs are isolated by high voltage diodes connected both at the two terminals of energy storage capacitors. The maximum energy per pulse per unit is in the range of 50 to 500 J, which means 200 to 2000J per pulse in total. The delay time between each two outputs can be changed from 5 to 200 μs by controlling the trigger signals of SCRs. The field test results show that larger delay time generates longer acoustic pulse width and smaller pulse amplitude. The spectrum results indicate the lower fundamental frequency for larger time interval.