Accelerating the pace of engineering and science

dfilt.dffir

Discrete-time, direct-form, FIR filter

Syntax

Hd = dfilt.dffir(b)
Hd = dfilt.dffir

Description

Hd = dfilt.dffir(b) returns a discrete-time, direct-form finite impulse response (FIR) filter, Hd, with numerator coefficients, b.

Hd = dfilt.dffir returns a default, discrete-time, direct-form FIR filter, Hd, with b=1. This filter passes the input through to the output unchanged.

The resulting filter states column vector is

$\left(\begin{array}{c}z\left(1\right)\\ z\left(2\right)\end{array}\right)$

Examples

Create a direct-form FIR discrete-time filter with coefficients from a 30th order lowpass equiripple design:

```b = firpm(30,[0 .1 .2 .5]*2,[1 1 0 0]);
Hd = dfilt.dffir(b)
```