- The processing of signals is called filtering. When applied to discrete-time signals, this processing is called digital filtering.
- Digital filters are defined by their impulse response, , or the filter output given a unit sample impulse input signal. A discrete-time unit impulse signal is defined by:
- The filtering operation in the time domain is referred to as convolution, defined as
- Digital filters are often more intuitively understood in terms of their frequency response. That is, how is a sinusoidal signal of a given frequency affected by the filter.
- One way to find the frequency response of a digital filter is by taking the DFT (or FFT) of the filter impulse response.
- The frequency response of a filter consists of its magnitude and phase responses. The magnitude response indicates the ratio of a filtered sine wave's output amplitude to its input amplitude. The phase response describes the phase “offset” or time delay experienced by a sine wave passing through a filter.

- A Basic Digital Filter:
- Finite Impulse Response (FIR) Filters:
- A Basic Digital Filter with Feedback:
- Infinite Impulse Response (IIR) Filters:
- Steady State and Transient Response:
- Filter Types and Descriptions
- Filter Combinations
- Resonance Filters
- Filtering in MSP
- Filters in Matlab

©2004-2021 McGill University. All Rights Reserved. Maintained by Gary P. Scavone. |