What is an indication that there is significant noise in a vibration spectrum?

A raised noise floor is indicative of significant noise in a vibration spectrum because it reflects the higher baseline level of noise present in the data. In a vibration analysis, a noise floor represents the level of background noise that is present in measurement signals. When the noise floor is raised, it can obscure smaller signals or peaks, making it difficult to identify true vibration frequencies or anomalies in the machinery being analyzed. This situation often makes it challenging to distinguish meaningful data from random fluctuations that do not correlate with actual machine conditions.

In contrast, clear frequency peaks typically indicate a well-defined signal rather than substantial noise, while low amplitude levels can suggest either minimal activity or effective noise containment. Perfectly symmetrical waveforms may indicate ideal operating conditions rather than the presence of significant noise. Thus, a raised noise floor directly points to the interference of noise in the data, leading to challenges in analyzing the vibration spectrum effectively.