Software-defined radio dongles are small and inexpensive receivers well known to amateur radio enthusiasts. When connected to an antenna, they enable monitoring of a wide range of the radio spectrum by conditioning the input signal and transferring a downconverted version of it to a personal computer for software processing. Here, we employ a composite of two such dongles, interfaced with codes written in MATLAB and GNU Radio, as a measuring instrument to study the flexural vibrations of a few-layer graphene nanomechanical resonator. Instead of an antenna, we connect the dongles to the split output of a photodetector used to detect vibrations optically. We first perform a quantitative analysis of the dynamics of the first vibrational mode. We then measure the response of the first two vibrational modes in parallel. To illustrate our technique, we detect changes in the vibrational amplitude of both modes induced by periodic strain modulation with a delay of ≈1\approx 1 ms between measurements. Last, we show that our software-based instrument can be employed to demodulate human voice encoded in the vibrations of our resonator. For parallel measurements of several frequency channels, and provided that the input signal is not too weak, our composite system may offer an alternative to the use of multiple lock-in amplifiers or multiple spectrum analyzers, with the distinct advantage of being cost-effective per frequency channel.

中文翻译：

---

具有递减优化的增量变分贝叶斯高斯混合模型，用于分布调节和精细尺度自适应过程监控


软件定义的无线电适配器是业余无线电爱好者熟知的小型且廉价的接收器。当连接到天线时，它们可以通过调节输入信号并将其下变频版本传输到个人计算机进行软件处理来监控广泛的无线电频谱。在这里，我们采用两个此类加密狗的组合，与用 MATLAB 和 GNU Radio 编写的代码连接，作为测量仪器来研究几层石墨烯纳米机械谐振器的弯曲振动。我们将加密狗连接到用于光学检测振动的光电探测器的分离输出，而不是天线。我们首先对第一振动模式的动力学进行定量分析。然后我们并行测量前两种振动模式的响应。为了说明我们的技术，我们检测了由周期性应变调制引起的两种模式的振动幅度的变化，测量之间的延迟为 ≈1\约 1 ms。最后，我们展示了基于软件的仪器可用于解调谐振器振动中编码的人声。对于多个频道的并行测量，并且只要输入信号不太弱，我们的复合系统可以提供使用多个锁定放大器或多个频谱分析仪的替代方案，其独特的优势是具有成本效益频率频道。