firtype
Type of linear phase FIR filter
Description
Examples
Types of Linear Phase Filters
Design two FIR filters using the window method, one of even order and the other of odd order. Determine their types and plot their impulse responses.
subplot(2,1,1) b = fir1(8,0.5); impz(b), title(['Type ' int2str(firtype(b))]) subplot(2,1,2) b = fir1(9,0.5); impz(b), title(['Type ' int2str(firtype(b))])
Design two equiripple Hilbert transformers, one of even order and the other of odd order. Determine their types and plot their impulse responses.
subplot(2,1,1) b = firpm(8,[0.2 0.8],[1 1],'hilbert'); impz(b), title(['Type ' int2str(firtype(b))]) subplot(2,1,2) b = firpm(9,[0.2 0.8],[1 1],'hilbert'); impz(b), title(['Type ' int2str(firtype(b))])
Types of FIR digitalFilter Objects
Use designfilt
to design the filters from the previous example. Display their types.
d1 = designfilt('lowpassfir','DesignMethod','window', ... 'FilterOrder',8,'CutoffFrequency',0.5); disp(['d1 is of type ' int2str(firtype(d1))])
d1 is of type 1
d2 = designfilt('lowpassfir','DesignMethod','window', ... 'FilterOrder',9,'CutoffFrequency',0.5); disp(['d2 is of type ' int2str(firtype(d2))])
d2 is of type 2
d3 = designfilt('hilbertfir','DesignMethod','equiripple', ... 'FilterOrder',8,'TransitionWidth',0.4); disp(['d3 is of type ' int2str(firtype(d3))])
d3 is of type 3
d4 = designfilt('hilbertfir','DesignMethod','equiripple', ... 'FilterOrder',9,'TransitionWidth',0.4); disp(['d4 is of type ' int2str(firtype(d4))])
d4 is of type 4
Input Arguments
b
— Filter coefficients
vector
Filter coefficients of the FIR filter, specified as a double- or single-precision real-valued row or column vector.
Data Types: double
| single
d
— FIR filter
digitalFilter
object
FIR filter, specified as a digitalFilter
object. Use
designfilt
to generate a
digital filter based on frequency-response specifications.
Output Arguments
t
— Filter type
1 | 2 | 3 | 4
Filter type, returned as either 1, 2, 3, or 4. Filter types are defined as follows:
Type 1 — Even-order symmetric coefficients
Type 2 — Odd-order symmetric coefficients
Type 3 — Even-order antisymmetric coefficients
Type 4 — Odd-order antisymmetric coefficients
Version History
Introduced in R2013a
See Also
MATLAB 명령
다음 MATLAB 명령에 해당하는 링크를 클릭했습니다.
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