this figure is the 3 dB bandwidth where phase and time delay render the signal essentially useless in a feedback loop. High speed position sensors are required with a bandwidth in the MHz that can provide accurate measurements at 100 kHz with negligible phase shift or time delay. Due to the operating principle of modulated sensors such as capacitive and inductive sensors, this level of performance is difficult to achieve due to the impractically high carrier frequency requirement. Applications requiring a very high sensor bandwidth typically use an auxiliary sensor for high bandwidth tasks, for example, a piezoelectric sensor can be used for active resonance damping [43,41]. Technologies such as piezoresistive sensors [91] have also shown promise in high-speed applications since a carrier frequency is not required. Magnetoresistive
sensors are also suitable for high frequency applications if the changes in field strength can be kept small enough to mitigate hysteresis [18,19