Filter Design Process Overview
Note
You must have the Signal Processing Toolbox™ installed
to use fdesign and filterBuilder.
Advanced capabilities are available if your installation additionally
includes the DSP System Toolbox™ license. You can verify the
presence of both toolboxes by typing ver at the
command prompt.
Filter design through user-defined specifications is the core
of the fdesign approach. This specification-centric
approach places less emphasis on the choice of specific filter algorithms,
and more emphasis on performance during the design a good working
filter. For example, you can take a given set of design parameters
for the filter, such as a stopband frequency, a passband frequency,
and a stopband attenuation, and— using these parameters—
design a specification object for the filter. You can then implement
the filter using this specification object. Using this approach, it
is also possible to compare different algorithms as applied to a set
of specifications.
There are two distinct objects involved in filter design:
Specification Object — Captures the required design parameters of a filter
Implementation Object — Describes the designed filter; includes the array of coefficients and the filter structure
The distinction between these two objects is at the core of the filter design methodology. The basic attributes of each of these objects are outlined in the following table.
| Specification Object | Implementation Object |
|---|---|
| High-level specification | Filter coefficients |
| Algorithmic properties | Filter structure |
If you want to access the full functionality of fdesign and
filterBuilder, you should additionally obtain the DSP System Toolbox software. You can verify the presence of these products by typing
ver at the command prompt.
