FIR_LowPass
Author : P Boyle, B F Schutz
Version : 2.0
Input Types : SampleSet
Output Types : SampleSet
Date : 23 February 2002
Contents
Description of FIR_LowPass
The unit called FIR_LowPass applies a time-domain FIR filter to the input
data set. The user can choose the order of the filter (number of points)
and the upper frequency limit on the passband. The user can also choose
whether to smooth the filter with a window function in the time-domain.
The filter is constructed from an ideal low-pass filter in the frequency
domain, converted to the time domain, truncated to the chosen number of
points, and multiplied by the chosen window function. The resulting filter
is convolved in the time domain with the input data set.
The user can choose whether to continue the convolution across successive
input data sets. In this case the unit will remember enough of the previous
data set to provide continuity of filtering, as if the two sets had been
concatenated before filtering.
For more information, see the help file on time-domain
filtering in Triana.
Using FIR_LowPass
FIR_LowPass' parameter
window (double-click on the unit) is used to select the upper bound on
the pass band, in Hz; the order of the filter (number of points used in
the time domain computation); and the windowing function used to smooth
the edges in the time-domain. The check box allows the user to determine
whether to treat successive input data sets as if they were a single concatenated
one to which the filter is applied in a continuous way.