Scanning probe microscopes are notoriously sensitive to many types of external and internal interferences including electrical, mechanical, and acoustic noise. Sometimes noise can even be misinterpreted as real features in the images. Therefore, quantification of frequency and magnitude of any noise is the key to discover the source and eliminate it from the system. While commercial spectrum analyzers are perfect for this task, they are rather expensive and not always available. We present a simple, cost-effective solution in the form of an audio output from the instrument coupled to a smart phone spectrum analyzer application. Specifically, the scanning probe signal, e.g., the tunneling current of a scanning tunneling microscope, is fed to the spectrum analyzer which Fourier transforms the time domain acoustic signal into the frequency domain. When the scanning probe is in contact with the sample, but not scanning, the output is a spectrum containing both the amplitude and frequency of any periodic noise affecting the microscope itself, enabling troubleshooting to begin.

中文翻译：

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低成本频谱分析仪，用于故障排除扫描探针显微镜中的噪声源

众所周知，扫描探针显微镜对多种类型的外部和内部干扰敏感，包括电，机械和声噪声。有时，噪点甚至可能被误解为图像中的真实特征。因此，量化任何噪声的频率和幅度是发现源并将其从系统中消除的关键。尽管商用频谱分析仪非常适合此任务，但它们价格昂贵且并非总是可用。我们提供一种简单，经济高效的解决方案，其形式是将仪器的音频输出耦合到智能手机频谱分析仪应用程序。具体地，扫描探针信号，例如扫描隧道显微镜的隧道电流，被馈送到频谱分析仪，该频谱分析仪傅立叶将时域声信号转换成频域。