Sparker pulses are released through manual or automatic triggering of the impulse generator (IPG5000) controlled by the remote control unit (RCU). e RCU converts the reference signal of the impulse generator to an accurate time break with an accuracy of a few microseconds.

To estimate the source repeatability the calculation of the coherency spectra is used. Coherency values of „1“ indicate perfect repeatability whereas a coherency of „0“ expresses no repeatability. e test shows that the P-wave sparker source SBS42 is highly repeatable up to frequencies of 4-5 kHz.