Anti-Oscillation Unit

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Choose the modules you need to measure nearly anything in muscle physiology

  • Neutralizes nearly 100% of the unavoidable transducer oscillation in optical force transducer
  • High time-resolution of the corrected force signal in ms range
  • Additional powerful signal smoothing with high time fidelity for all higher harmonics
  • For use with the SI-BMFA



  • Goes beyond traditional low-pass filtering of an oscillated signal
  • No phase-shift in the force signal
  • High time fidelity in following the applied step signal


  • All types of optical-based force measurements

Within a force transducer, the applied force displaces an elastic component of the transducer. This displacement is transformed into an electrical signal. If the displacement of the elastic component is small and if the displacement is linearly transformed into an electrical signal, the external force and electrical signal are linearly related to each other.

However, shortly after the force changes rapidly the electrical signal does not follow the applied force linearly, as the elastic element and the force transducer pin have a mass. So, the system acts not only as an elastic device but also as a harmonic oscillator, notably when the force changes rapidly, resulting in oscillation of the system around the new displacement level (ringing phenomenon).

To address this problem, WPI’s Anti-Oscillation Unit (SI-AOSUB) uses a genuine electronic approach to remove the unavoidable transducer oscillation, based on electronic differentiation of the force signal and subsequent low-pass filtering of the resulting high-frequency signal. 

The upper trace is a force transient obtained directly from the bridge amplifier output, and the lower trace shows the signal after it passes through the “anti oscillation” unit.

To adjust the anti-oscillation filter properly, the transducer is excited at its resonance frequency using a magnetic driver or pulser (WPI #97204). The Pinger (WPI #97204) is included with the anti-oscillation module.



Power 12 VDC provided by chassis
Input ± 10 VDC
Pulser Output 0 – 10 VDC adjustable
0.1 Hz – 4.0 KHz
Damping Frequency Range 0.1 Hz – 2.0 KHz
Output Range ± 10 VDC




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