The SP-801A produces negative high power square pulses with fast rise and fall times with an extremely low output impedance (~ 4 Ohms). The pulse width can be precisely matched (continuously variable) to the half period of the frequency (50 kHz to 20 MHz with four adjustable ranges) of an ultrasonic transducer. This maximizes the energy transfer and signal-to-noise ratio for a given voltage output and is, therefore, significantly more effective than a spike pulser. This is especially true at low frequencies. The output level is adjustable in 2-dB steps, from -400 Volts down to -50 Volts.