1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
function a=lsf2poly(lsf)
//lsf2poly function convert line spectral frequencies to prediction polynomial.
// Calling Sequence
// a = lsf2poly(lsf)
// Parameters
// lsf: define line spectral frequencies.
// a: Return the prediction polynomial.
// Examples
//X = [0.5 0.752 1.6 1.8 2.45 0.8]
// a = lsf2poly(X)
//
// See also
//
// Author
// Jitendra Singh
//
if isempty(lsf) then
a=[];
else
if or(type(lsf)==10) then
error ('Input arguments must be double.')
end
if ~isreal(lsf) then
error ('Line spectral frequencies must be real.')
end
if max(lsf)>%pi | min(lsf)<0 then
error ('Line spectral frequencies must be between 0 and pi.')
end
if size(lsf,1)==1 & size(lsf,2) then
error('Input should be vector of length more than one or matrix.')
end
if isvector(lsf) then
lsf=lsf(:);
end
lsf1=lsf;
n=size(lsf1);
c=n(2);
for i=1:c
lsf2=lsf1(:,i);
lsf2=lsf2(:);
nn=length(lsf2);
ImgReal=exp(%i*lsf2);
odd=ImgReal(1:2:$);
even=ImgReal(2:2:$);
odd1=[odd; conj(odd)];
even1=[even; conj(even)];
odd2= poly(odd1, 'x');
odd2=real(odd2);
odd2=flipdim(coeff(odd2), 2,1);
even2= poly(even1,'x');
even2=real(even2);
even2=flipdim(coeff(even2),2, 1);
if (nn-fix(nn./2).*2)~=0 then
even3=conv(even2, [1 0 -1]);
odd3=odd2;
else
odd3=conv(odd2, [1 1]);
even3=conv(even2, [1 -1]);
end
aa=0.5*(odd3+even3);
aa($)=[];
aaa(i,:)=aa;
end
a=aaa;
end
endfunction
|
