Digital notch filter

1. What is a digital notch filter?
2. What does notch filter do on EEG?
3. Why is notch filter used in ECG?
4. What does the 60 Hz notch filter do?

What is a digital notch filter?

Notch filters are used to remove a single frequency or a narrow band of frequencies. In audio systems, a notch filter can be used to remove interfering frequencies such as powerline hum. Notch filters can also be used to remove a specific interfering frequency in radio receivers and software-defined radio.

What does notch filter do on EEG?

A notch filter is typically an aggressive filter that strongly attenuates the power over a narrow region of the spectrum. For example, a notch filter at 60 Hz / 50 Hz is used to filter out power line noise with minimal disruption to the rest of the signal.

Why is notch filter used in ECG?

Several kinds of notch filters (analog and digital) were implemented for evaluation of the distortion caused on ECG signals. These filters were applied to ECGs of humans and rats and then distortion estimates were computed from their resulting signals.

What does the 60 Hz notch filter do?

Notch filters can be useful on the command for a fixed-frequency noise source such as that from line frequency (50 or 60 Hz) noise. Notch filters are also used to remove resonances from the system. Both notch and low-pass filters can cure resonance; notch filters do so while creating less phase lag in the control loop.