Frequency response of a z-stage mounted in the scan head measured from 200 Hz up to 100 kHz. To increase signal/noise at low frequencies, the applied amplitude was 10.0 V peak-to-peak from 200 Hz to 10 kHz. Above this, it was reduced to 3.0 V peak-to-peak to keep the large signal swings at the resonance peak within the limits of the measurement system.