User`s guide

1 Data Processing
In this case, w1 an d wh represent the low and high frequencies of the passband,
respectively.
You can specify several passbands, as follows:
filter=[[w1l,w1h];[ w2l,w2h]; ....;[wnl,wnh]]
The filter is an n -by- 2 matrix, where each row defines a passband in radians
per second.
To define a stopband between
ws1 and ws2,use
filter = [0 ws1; ws2 Nyqf]
where, Nyqf is the Nyquist frequency.
For time-domain data, the passband filtering is cascaded B utterworth filters of
specified order. The default filter order is 5. The Butterworth filter is the same
as
butter in the Sig n al Processin g Toolbox produc t. For frequency-domain
data, select t he indicated portions of the data to perform passband filtering.
Defining a Custom Filter
Use id filt to apply passband and other custom filters to a time-domain or
a frequency-domain
iddata object.
In ge nera l, you ca n specify any custom filter. Use this syntax to filter an
iddata object data using the filter called fi lter :
fdata = idfilt(data,filter)
You can define a general single-input/single-output (SISO) system for filtering
time-domain or frequency-domain data. For frequency-domain only, you can
specify the (nonparametric) frequency response of the fi lter.
You use this syntax to filter an
iddata object data using a custom filter
specified by
filter:
fdata = idfilt(data,filter)
filter
canbealsoanyofthefollowing:
1-112