Which type of filter would you use to remove lower frequency noise from a physiological signal?

A high-pass filter is designed to allow signals with a frequency higher than a certain cutoff frequency to pass through while attenuating signals with frequencies lower than that cutoff. This characteristic makes high-pass filters particularly useful in applications where it is essential to eliminate lower frequency noise or interference from the physiological signals being measured.

In the context of physiological signals, sources of lower frequency noise can include baseline wander or movement artifacts that can distort the true signal of interest. By applying a high-pass filter, you effectively clean the signal, preserving the higher frequency components that are typically of interest in physiological monitoring, such as electromyography (EMG) or electrocardiography (ECG).

A band-stop filter would not be suitable for this purpose, as it is designed to attenuate a specific range of frequencies rather than allowing higher frequencies to pass while blocking lower ones. A low-pass filter is aimed at removing high-frequency noise, making it ineffective for the goal of eliminating lower frequency interference. Finally, a notch filter is used to remove a very specific frequency band, which is not ideal for general low-frequency noise removal.