|
power spectrum estimation 有幾種方式,& V" N7 @* R+ o% b6 A" q
Peroidogram1 w* a" i J+ P, |: x
Modified periodogram
$ J, F: C& p6 q9 iBartlett method
D6 D; G5 C$ D4 zWelch method7 x4 b }4 Y; l" c7 q: u
Blackman-Tukey method
+ S1 c" ^# w6 r' H/ L6 G ^3 t+ G
' H8 j: j9 H9 H1 ^若用simple Peroidogram m file 方式如下,estimated 跟 actual 會有Bias
- A9 |, g6 Q$ A+ h( P! b# z! k& _, Zx : input sequence
: H2 R3 o/ I5 y7 ?+ ^0 C* v9 i# mn1 : starting index, x(n1)+ A5 w% R% B4 E" r# U( w- e& M
n2 : ending index, x(n2)7 m. [( S- ~/ Y5 T! x8 c) q
! ?# G: j) i" @: N) t2 O8 T) Nfunction Px = per(x,n1,n2)1 I6 |& S; S1 E0 M$ L2 \
x = x(;& d2 Q. r1 y# ]' Z3 {
if nargin == 10 W2 U3 @/ ]$ t+ x# }7 p
n1 = 1; n2 = length(x); end;
/ q. t: z& B) v: Y6 LPx = abs(fft(x(n1:n2),1024)).^2/(n2-n1+1);4 x: j5 n0 L! N1 m' X# ?4 @
Px(1) = Px(2); |
|