Frequency SweepΒΆ

_images/frequency_sweep.png

After loading the cantilever and adjusting the detector, find the cantilever resonance by sweeping the frequency of the cantilever drive signal while measuring the detector response signal. The Frequency Sweep panel opens when you click the top icon in the work-flow.

Run sweep starts the measurement between the Start frequency [kHz] and Stop frequency [kHz]. Edit these fields to change the sweep range. The sweep range should include the likely resonance frequency of the cantilever, which should be provided by the probe manufacturer and is usually printed on the probe box. Reducing the measurement Bandwidth [kHz] causes the sweep to be slower and the measured response to be more accurate. The sweep speed also depends on the Number of points recorded during the sweep. The measurement time at each point is given by the inverse of the bandwidth. You may need to adjust the Drive amplitude [V] in order to the right amount of excitation to excite the cantilever resonance.

Check boxes provide automatic features for finding the resonance and controlling the sweep:

  • Zoom peak performs a second sweep with finer detail, zoomed in on the peak response found in the sweep range.
  • Transfer results to noise calibration transfers the center frequency and estimated sweep range to the next stage in the work flow.
  • Reverse sweep direction gives a sweep with increasing and then decreasing frequency over the range specified.