dfilt.cascade (Signal Processing Toolbox)

Construct a cascade of discrete-time filter objects

Syntax

```
Hd = dfilt.cascade(Hd₁,Hd₂,...)
```

Description

Hd = dfilt.cascade(Hd1,Hd2,...) returns a discrete-time filter object, Hd, of type cascade, which is a serial interconnection of two or more dfilt filter objects, Hd1, Hd2, and so on.

You can also use the nondot notation format for calling a cascade:

```
cascade(Hd1,Hd2,...)
```

Examples

Cascade a lowpass filter and a highpass filter to produce a bandpass filter:

[b1,a1]=butter(8,0.6);            %Lowpass
[b2,a2]=butter(8,0.4,'high');     %Highpass
H1=dfilt.df2t(b1,a1);
H2=dfilt.df2t(b2,a2);
Hcas=dfilt.cascade(H1,H2)         %Bandpass with passband 0.4-0.6

dfilt dfilt.df1