如何用FFT來計算SNR及THD

TJ球

我用FFT軟體算出x=[1,2,3,4,5,4,3,2]8個序列點的值，
$ f( l6 |( t% H! z$ o/ z
+ L* S  n! u5 J! S* mX[0] = 24+(0)j
X[1] = -6.82842712475+(-1.33226762955E-15)j
X[2] = 3.09539720245E-17+(0)j
X[3] = -1.17157287525+(2.88657986403E-15)j
X[4] = 0+(-4.89842541529E-16)j
X[5] = -1.17157287525+(-2.44249065418E-15)j
: X+ c0 D- z; _* }3 J- A# z& A6 cX[6] = -9.86282453277E-15+(-6.66133814775E-16)j
7 h# e* O& ]0 R; u" |" z9 ]9 c! XX[7] = -6.82842712475+(-2.22044604925E-15)j
. D$ J9 {  M3 N- J
; |3 x7 ]! C" G我該如何藉由這些值算出SNR及THD呢?