Cascade of discrete-time filters
dfilt.cascade in Signal Processing Toolbox™ documentation
for more information.
hd = dfilt.cascade(filterobject1,filterobject2,...) returns
a discrete-time filter object
hd of type
which is a serial interconnection of two or more filter objects
and so on.
dfilt.cascade accepts any combination
dfilt objects (discrete time filters) to cascade,
as well as Farrow filter objects.
You can use the standard notation to cascade one or more filters:
hd2, and so
on can be mixed types, such as
dfilt objects and
hd2, and so on can
be fixed-point filters. All filters in the cascade must be the same
arithmetic format —
hd, the filter object
returned, inherits the format of the cascaded filters.
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 % View stage 1 with hcas.Stage(1)