Filter Design Toolbox™

coeffs - Coefficients for filters

Syntax

s = coeffs(ha) s = coeffs(hd) s = coeffs(hm)

Description

The next sections describe common coeffs operation with adaptive, discrete-time, and multirate filters.

Adaptive Filters

s = coeffs(ha) returns a structure s containing the coefficients of adaptive filter ha. These are the instantaneous filter coefficients available at the time you use the function.

Discrete-Time Filters

s = coeffs(hd) returns a structure s that contains the coefficients of discrete-time filter hd.

Multirate Filters

s = coeffs(hm) returns s, a structure containing the coefficients of discrete-time filter hm. CIC-based filters do not have coefficients and this function does not work with constructors like mfilt.cicdecim.

Examples

coefficients works the same way for all filters. This example uses a multirate filter hm to demonstrate the function.

hm=mfilt.firdecim(3)
 
hm =
 
         FilterStructure: 'Direct-Form FIR Polyphase Decimator'
               Numerator: [1x72 double]
        DecimationFactor: 3
        PersistentMemory: false
                  States: [69x1 double]

s=coeffs(hm)

s = 

    [1x72 double]

s.Numerator

ans =

  Columns 1 through 8 

         0   -0.0000   -0.0001         0    0.0002    0.0003         0   -0.0005

  Columns 9 through 16 

   -0.0007         0    0.0011    0.0014         0   -0.0022   -0.0028         0

  Columns 17 through 24 

    0.0040    0.0048         0   -0.0068   -0.0080         0    0.0111    0.0129

  Columns 25 through 32 

         0   -0.0177   -0.0207         0    0.0287    0.0342         0   -0.0513

  Columns 33 through 40 

   -0.0659         0    0.1363    0.2749    0.3333    0.2749    0.1363         0

  Columns 41 through 48 

   -0.0659   -0.0513         0    0.0342    0.0287         0   -0.0207   -0.0177

  Columns 49 through 56 

         0    0.0129    0.0111         0   -0.0080   -0.0068         0    0.0048

  Columns 57 through 64 

    0.0040         0   -0.0028   -0.0022         0    0.0014    0.0011         0

  Columns 65 through 72 

   -0.0007   -0.0005         0    0.0003    0.0002         0   -0.0001   -0.0000