butfilt {RSEIS} | R Documentation |
design and apply butterworth low/high/band pass filters.
butfilt(a, fl=0, fh=50, deltat=1, type="BP", proto="BU", npoles=5, chebstop=30.0, trbndw=0.3)
a |
vector signal |
fl |
low frequency cut-off, default=0 |
fh |
high frequency cut-off, DEFAULT=1/2dt |
deltat |
sample rate, s, deFAULT=1 |
type |
type of filter, one of c("LP", "HP","BP" ,"BR" ), DEFAULT="BP" |
proto |
prototype, c("BU", "BE" , "C1" ,"C2"), DEFAULT="BU" |
npoles |
number of poles or order, DEFAULT=5 |
chebstop |
Chebyshev stop band attenuation, DEFAULT=30.0 |
trbndw |
Chebyshev transition bandwidth, DEFAULT=0.3 |
creation of butfilt is a described by the following arguments:
Arguments chebstop , trbndw are ignored for non-chebyshev filters. LP and HP filters are seet by specifying fl for HP filters and fh for LP filters, the other argumentin each case is ignored.
filtered time series
Jonathan M. Lees<jonathan.lees.edu>
data(CE1) ts1 = CE1$y zz = butfilt(ts1, 1, 15, CE1$dt, "LP" , "BU")