What is typically displayed in a frequency spectrum?

In a frequency spectrum, the primary focus is on representing various frequencies and their amplitudes present in a signal. When observing a frequency spectrum from a vibration analysis perspective, it typically displays not only the fundamental frequency but also any modulation effects and sidebands that may be present around this fundamental frequency.

The presence of modulation effects indicates how the frequency of a waveform varies over time, often resulting from interactions within mechanical components or external influences. The sidebands appear as additional peaks in the spectrum surrounding the fundamental frequency, indicating these interactions and contributing to the overall vibrational behavior of the system. Hence, a frequency spectrum provides valuable insight into the dynamic characteristics of mechanical systems, including potential issues related to imbalances, misalignments, or other anomalies.

The other options do not encapsulate the full scope of what a frequency spectrum portrays. For instance, displaying solely the fundamental frequency does not provide a comprehensive view of the system's behavior. A mere collection of frequencies of mechanical components does not address the complexities introduced by modulation and sidebands. Lastly, frequency spectra do not depict thermal data, such as heat generated by the equipment, which is an entirely different analytical domain.