What is the effect of a low-frequency filter?

A low-frequency filter is designed to allow low frequencies to pass through while attenuating higher frequencies. In the context of polysomnography, this type of filter is important for eliminating electrical noise and other high-frequency artifacts that can interfere with the analysis of slower brain waves, such as delta and theta waves, which are crucial for understanding sleep states.

The function of a low-frequency filter is to maintain the integrity of the important low-frequency signals while reducing the impact of higher-frequency noises, which are not relevant to the analysis of sleep patterns or other physiological measurements in polysomnography. This selective filtration is essential for producing clearer and more interpretable data that reflects the true state of the patient's sleep or other measured phenomena. Thus, by allowing low frequencies to pass, the low-frequency filter enhances the quality of the recorded data.