A Quartz Crystal Microbalance (QCM) is a highly sensitive device based on the measurement of the resonance\udparameters of a thickness-shear piezoelectric resonator, which classical application is the detection\udof attached mass per unit area. Although the most economical ways of driving these sensors make use of\udoscillator circuits, other electronic interfaces are also well-established, i.e., electrical impedance analysis\udand impulse excitation/decay methods. Impulse excitation and decay methods are founded on the same\udprinciple, but in practice only the latter has been exploited. The present work explores the suitability\udof a broadband spike excitation technique (up to 0.25 GHz) as an interface electronic system for QCM\udsensors. The principles of measurement—including the processing of signals—are described in detail and\udillustrated for liquids with different mechanical shear impedances. The proposed mode of operation has\udproved some advantageous characteristics: both resonant frequency and energy dissipation can be simultaneously\uddetermined in a wide range of frequencies; it is appropriate for in-liquid sensing applications\ud(including highly viscous liquids); it can be easily automated for continuous monitoring and integrated\udwith other external circuitry (such as multiplexing for sensor arrays)
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