Frequency response
Experimental setup and frequency response. (a) The nonlinear response
of the beam displays notable hysteresis and bistability. The curve of
upright triangles represents the response of the system when the frequency is
swept upward, while the inverted triangles demonstrate the response seen
when sweeping down. (Inset) When excited by a force of approximately
96 piconewtons, the bridge displays classically linear behaviour. The two states correspond in voltage to the upper and lower extremes of the hysteresis curves (b) Schematic of the electrical circuit used in measuring the nonlinear response of the beam (image and text: Appl. Phys. Lett. 85 3587)