diff options
Diffstat (limited to 'macros/kaiserord.sci')
| -rw-r--r-- | macros/kaiserord.sci | 94 |
1 files changed, 60 insertions, 34 deletions
diff --git a/macros/kaiserord.sci b/macros/kaiserord.sci index 47f4105..5f46193 100644 --- a/macros/kaiserord.sci +++ b/macros/kaiserord.sci @@ -10,7 +10,6 @@ function [n, Wn, beta, ftype] = kaiserord (f, m, dev, fs) //dev: Deviation of the filter. //fs: Sampling rate. //Description -//This is an Octave function. //The vector f contains pairs of frequency band edges in the range [0,1]. The vector m specifies the magnitude response for each band. The values of m must be zero for all stop bands and must have the //same magnitude for all pass bands. The deviation of the filter dev can be specified as a scalar or a vector of the same length as m. The optional sampling rate fs can be used to indicate that f is in //Hz in the range [0,fs/2]. @@ -28,43 +27,70 @@ function [n, Wn, beta, ftype] = kaiserord (f, m, dev, fs) // n = (A-8)/(2.285 dw) //Examples //[n, w, beta, ftype] = kaiserord ([1000, 1200], [1, 0], [0.05, 0.05], 11025) -//n = 1 -//w = 1100 +//n = 70 +//w = 0.199 //beta = 1.5099 //ftype = low -funcprot(0); -lhs = argn(1) -rhs = argn(2) -if (rhs < 3 | rhs > 4) +if (argn(2) < 3 | argn(2) > 4) error("Wrong number of input arguments.") end -select(rhs) - - case 3 then - if(lhs==1) - n = callOctave("kaiserord",f, m, dev) - elseif(lhs==2) - [n, Wn] = callOctave("kaiserord",f, m, dev) - elseif(lhs==3) - [n, Wn, beta] = callOctave("kaiserord",f, m, dev) - elseif(lhs==4) - [n, Wn, beta, ftype] = callOctave("kaiserord",f, m, dev) - else - error("Wrong number of output argments.") - end - case 4 then - if(lhs==1) - n = callOctave("kaiserord",f, m, dev, fs) - elseif(lhs==2) - [n, Wn] = callOctave("kaiserord",f, m, dev, fs) - elseif(lhs==3) - [n, Wn, beta] = callOctave("kaiserord",f, m, dev, fs) - elseif(lhs==4) - [n, Wn, beta, ftype] = callOctave("kaiserord",f, m, dev, fs) - else - error("Wrong number of output argments.") - end - end + + if argn(2)<4 then + fs=2; + end + + if length(f)~=(2*length(m)-2) then + error("kaiserord must have one magnitude for each frequency band"); + end + + if or(m(1:length(m)-2)~=m(3:length(m))) then + error("kaiserord pass and stop bands must be strictly alternating"); + end + if length(dev)~=length(m) & length(dev)~=1 then + error("kaiserord must have one deviation for each frequency band"); + end + dev = min(dev); + if dev <= 0 then + error("kaiserord must have dev>0"); + end + Wn = (f(1:2:length(f))+f(2:2:length(f)))/fs; + + if length(Wn) == 1 then + if m(1)>m(2) then + ftype='low'; + else + ftype='high'; + end + elseif length(w) == 2 then + if m(1)>m(2) then + ftype='stop'; + else + ftype='pass'; + end + else + if m(1)>m(2), + ftype='DC-1'; + else + ftype='DC-0'; + end + end + + A = -20*log10(dev); + if (A > 50) + beta = 0.1102*(A-8.7); + elseif (A >= 21) + beta = 0.5842*(A-21)^0.4 + 0.07886*(A-21); + else + beta = 0.0; + end + + dw = 2*%pi*min(f(2:2:length(f))-f(1:2:length(f)))/fs; + n = max(1,ceil((A-8)/(2.285*dw))); + + if ((m(1)>m(2)) == ((length(Wn)-fix(length(Wn)./2).*2)==0)) & (n-fix(n./2).*2)==1 then + n = n+1; + end + endfunction |