Digital Signal Processing Reference
In-Depth Information
problem
2
. This FDA Tool finite design-analysis (FDA) tool, found in the Filter
Design Toolbox, works in conjunction with the Signal Processing (SP) Toolbox.
Unlike the SP Toolbox, the FDA Tool has been developed by making extensive use
of the object-oriented programming capability of MATLAB, and the syntax for the
functions available in the FDA Tool is different from the syntax for the functions
we find in MATLAB and the SP Toolbox. When we log on to MATLAB and type
fdatool
, we get two screens on display. On one screen, we type the
fdatool
functions as command lines to design and analyze quantized filters, whereas the
other screen is a graphical user interface (GUI) to serve the same purpose. The
GUI window shown in Figure 7.1a displays a dialog box with an immense array
of design options as explained below.
First we design a filter with double precision on the GUI window using the
FDA Tool or on the command window using the Signal Processing Toolbox and
then import it into the GUI window. In the dialog box for the FDA Tool, we can
choose the following options under the
Filter Type
panel:
1.
Lowpass
2.
Highpass
3.
Bandpass
4.
Bandstop
5.
Differentiator. By clicking the arrow on the tab for this feature, we get
the following additional options.
6.
Hilbert transformer
7.
Multiband
8.
Arbitrary magnitude
9.
Raised cosine
10.
Arbitrary group delay
11.
Half-band lowpass
12.
Half-band highpass
13.
Nyquist
Below the
Filter Type
panel is the panel for the design method. When the
button for IIR filter is clicked, the dropdown list gives us the following options
specifying the type of frequency response:
•
Butterworth
•
Chebyshev I
•
Chebyshev II
•
Elliptic
•
Least-
p
th norm
•
Constrained least-
p
th norm
2
The author acknowledges that the material on the FDA Tool described in this chapter is based on
the
Help Manual for Filter Design Toolbox
found in MATLAB version 6.5.
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