Filter Design
You can design and analyze a variety of digital FIR and IIR filters using DSP System Toolbox™ functions, apps, and blocks. Some of these filters include advanced filters such as Nyquist filters, halfband filters, CIC filters, advanced equiripple filters, and quasi-linear phase IIR filters.
The design techniques compute the filter coefficients based on the filter design specifications. Certain blocks such as Bandpass IIR Filter Design and Bandstop IIR Filter Design have tunable filter specifications, so you can change the filter specifications and redesign the filter while the simulation is running.
Apps
| Filter Designer | Design filters by choosing algorithm or specifying constraints |
Live Editor Tasks
| Design Filter | Design a digital filter or implement a System object in the Live Editor (Since R2021b) |
Functions
Objects
Filter Responses
Blocks
Topics
- Use Filter Designer App
Import or create filters, design, inspect, and export filter designs.
- STEP 1: Import or Create Filters
- STEP 2: Design Filters
- STEP 3: Quantize Filters
- STEP 4: Manage and Analyze Filters
- STEP 5: Export and Share Filters
- Design a Filter in Fdesign — Process Overview
Learn how to analyze, design, and implement filters in MATLAB® and Simulink®.
- Lowpass FIR Filter Design
This example shows how to design a lowpass FIR filter using
fdesign. - Lowpass Filter Design in MATLAB
This example shows how to design lowpass filters.
- Controlling Design Specifications in Lowpass FIR Design
This example shows how to control the filter order, passband ripple, stopband attenuation, and transition region width of a lowpass FIR filter.
- Minimax FIR Filter Design
This example shows how to use some of the key features of the generalized Remez FIR filter design function.
- Designing Filters with Non-Equiripple Stopband
This example shows how to design lowpass filters with stopbands that are not equiripple.
- Minimizing Lowpass FIR Filter Length
This example shows how to minimize the number coefficients, by designing minimum-phase or minimum-order filters.
- References — Advanced Filters
Suggested reading and sources for advanced filter design topics.
Featured Examples
IIR Halfband Stages in Multistage Filter Design
Discusses IIR halfband stages in multistage decimators and interpolators.
Classic IIR Filter Design
Design classic IIR filters. The example initially focuses on the scenario where critical design parameter is the cutoff frequency at which the power of the filter decays to half (–3 dB) the nominal passband value.
Design Peak and Notch Filters
Design peak and notch filters. Filters that peak or notch at a certain frequency retain or eliminate a particular frequency component of a signal. The design parameters that you can set for such filters are the frequency at which you want the peak or notch and the 3-dB bandwidth or the Q factor. Using these specifications and by increasing the filter order, you can design filters that more closely approximate an ideal filter.
Arbitrary Magnitude and Phase Filter Design
Design filters with customized magnitude and phase specifications. Many filter design problems focus on the magnitude response only, while assuming a linear phase response through symmetry. In some cases, however, the desired filter needs to satisfy constraints on both magnitude and phase.
Least Pth-Norm Optimal FIR Filter Design
Design least Pth-norm FIR filters with the firlpnorm function. This function uses a least-Pth unconstrained optimization algorithm to design FIR filters with arbitrary magnitude response.
Least Pth-Norm Optimal IIR Filter Design
Design optimal IIR filters with arbitrary magnitude response using the least-Pth unconstrained optimization algorithm.
FIR Nyquist (L-th band) Filter Design
Design lowpass FIR Nyquist filters. It also compares these filters with raised cosine and square root raised cosine filters. These filters are widely used in pulse-shaping for digital transmission systems. They also find application in interpolation/decimation and filter banks.
Design of Decimators and Interpolators
Design filters for decimation and interpolation of discrete sequences.
IIR Filter Design Given a Prescribed Group Delay
Design arbitrary group delay filters using the designfilt. This designer uses a least-Pth constrained optimization algorithm to design allpass IIR filters that meet a prescribed group delay.
Fractional Delay Filters Using Farrow Structures
Use Farrow structures to design digital fractional delay filters. Digital fractional delay filters are useful tools to fine-tune the sampling instants of signals. They are typically found in the synchronization of digital modems where the delay parameter varies over time. This example illustrates why the Farrow structure is a popular method for implementing time-varying FIR fractional delay filters.
Design Fractional Delay FIR Filters
Design an implementation of fractional delay FIR filters.
