The 60-Hz notch filter is used to eliminate?

The 60-Hz notch filter is specifically designed to eliminate interference caused by electrical devices, particularly the hum from alternating current (AC) power sources in North America, which operates at a frequency of 60 Hz. This type of interference is commonly referred to as "power line noise" or "electrical artifact."

In a polysomnographic setting, when monitoring a patient, this noise can obscure important physiological signals, leading to inaccurate interpretations of the data. By applying a 60-Hz notch filter, technologists can effectively reduce this interference, allowing for clearer readings of brain waves, muscle activity, and other vital signs captured during the sleep study.

Muscle artifacts, respiratory signals, and cardiac interference are not effectively filtered by the 60-Hz notch filter as they occur at different frequencies and are related to physiological activities rather than electrical noise. Thus, this filter is a critical tool in ensuring the quality of polysomnographic recordings by providing a cleaner signal free from such irrelevant electrical noise.