We demonstrate a novel technique for operating a differentially-driven and differentially-sensed double-sided comb-drive resonator. The resonator is driven by application of two out-of-phase ac signals to the drive stators, while the rotor is subjected to a pure harmonic signal at the same frequency as of the ac driving signals. In this mode of operation, no dc bias is necessary. This strategy results in two frequency-mixing operations, such that a clear response can be sensed at the 3rd harmonic of the drive signal. Besides the responses in the 1st and 3rd harmonics of the drive frequency, no other higher-harmonic components are predicted from the analysis or observed in the measurements. With harmonic biasing, the resonator is insensitive to both feed-through currents that result from direct capacitive cross-coupling of sense and drive pads, and to feed-through currents that result from imbalanced sense ports due to packaging and setup. We show that a clear response can be achieved for low-power drive signals, whereas if the system were driven as a classic resonator with a dc bias on the rotor, the response would have been overshadowed by feed-through. We also demonstrate that the phase of the sensed response can be modified by varying the phase of the harmonic bias on the rotor.

我们展示了一种用于操作差分驱动和差分感测的双面梳状驱动谐振器的新技术。通过向驱动定子施加两个异相交流信号来驱动谐振器，而转子则受到与交流驱动信号频率相同的纯谐波信号的影响。在这种操作模式下，不需要直流偏置。这种策略会导致两个混频操作，从而可以在驱动信号的 3 次谐波处检测到清晰的响应。除了驱动频率的 1 次和 3 次谐波的响应外，没有从分析中预测或在测量中观察到其他高次谐波分量。通过谐波偏置，谐振器对感应和驱动焊盘的直接电容交叉耦合产生的馈通电流不敏感，以及由于封装和设置导致的感测端口不平衡导致的馈通电流。我们表明，对于低功率驱动信号可以实现清晰的响应，而如果系统被驱动为转子上带有直流偏置的经典谐振器，则响应将被馈通所掩盖。我们还证明，可以通过改变转子上谐波偏置的相位来修改感测响应的相位。