Ultrasound medical devices, systems and methods are described. According to an example method, an absolute value of a first input to a voltage controlled oscillator (VCO) is determined. The VCO is in electrical communication with an acoustic assembly of an ultrasound medical device. If the absolute value of the first input to the VCO is in a first range, a second input to the VCO is maintained. If the absolute value of the first input to the VCO is in a second range, the second input to the VCO is adjusted by a first voltage. If the absolute value of the first input to the VCO is in a third range, the second input to the VCO is adjusted by a second voltage.