例題3 FIR 線形位相フィルタ

組み込み関数 wfir

wfir(1) Scilab Function wfir(1)
NAME
wfir - linear-phase FIR filters

CALLING SEQUENCE
[wft,wfm,fr]=wfir(ftype,forder,cfreq,wtype,fpar)

PARAMETERS

ftype
: string : 'lp','hp','bp','sb' (filter type)

forder
: Filter order (pos integer)(odd for ftype='hp' or 'sb')

cfreq
: 2-vector of cutoff frequencies (0<cfreq(1),cfreq(2)<.5)
only cfreq(1) is used when ftype='lp' or 'hp'

wtype
: Window type ('re','tr','hm','hn','kr','ch')

fpar : 2-vector of window parameters. Kaiser window fpar(1)>0 fpar(2)=0.
Chebyshev window fpar(1)>0, fpar(2)<0 or fpar(1)<0, 0<fpar(2)<.5

wft : time domain filter coefficients

wfm : frequency domain filter response on the grid fr

fr : Frequency grid

DESCRIPTION
Function which makes linear-phase, FIR low-pass, band-pass, high-pass, and
stop-band filters using the windowing technique. Works interactively if
called with no arguments.

AUTHOR
C. Bunks

インパルスレスポンスのプロット

-->[h,hm,fr]=wfir('bp',55,[.20 .25],'hm',[0 0])

-->plot(h)

描かれた図

ホームに戻る