dfilt.df2
Discrete-time, direct-form II filter
Syntax
Hd = dfilt.df2(b,a)
Hd = dfilt.df2
Description
Hd = dfilt.df2(b,a)
returns a
discrete-time, direct-form II filter, Hd
, with numerator coefficients
b
and denominator coefficients a
.
Hd = dfilt.df2
returns a default,
discrete-time, direct-form II filter, Hd
, with b
=1
and a
=1. This filter passes the input through to the output
unchanged.
Note
The leading coefficient of the denominator a(1)
cannot be 0.
The resulting filter states column vector is
Examples
Create a direct-form II discrete-time filter with coefficients from a fourth-order lowpass Butterworth design:
[b,a] = butter(4,.5); Hd = dfilt.df2(b,a)
Version History
Introduced before R2006a