52 lines
1.3 KiB
Fortran
52 lines
1.3 KiB
Fortran
subroutine baselinejs8(s,nfa,nfb,sbase)
|
|
|
|
! Fit baseline to spectrum (for JS8)
|
|
! Input: s(npts) Linear scale in power
|
|
! Output: sbase(npts) Baseline
|
|
|
|
implicit real*8 (a-h,o-z)
|
|
|
|
!include 'js8_params.f90'
|
|
|
|
real*4 s(NSPS)
|
|
real*4 sbase(NSPS)
|
|
real*4 base
|
|
real*8 x(1000),y(1000),a(5)
|
|
data nseg/10/,npct/10/
|
|
|
|
df=12000.0/(NSPS*2.0d0) !3.125 Hz
|
|
ia=max(1,nint(nfa/df))
|
|
ib=nint(nfb/df)
|
|
do i=ia,ib
|
|
s(i)=10.0*log10(s(i)) !Convert to dB scale
|
|
enddo
|
|
|
|
nterms=5
|
|
nlen=(ib-ia+1)/nseg !Length of test segment
|
|
i0=(ib-ia+1)/2 !Midpoint
|
|
k=0
|
|
do n=1,nseg !Loop over all segments
|
|
ja=ia + (n-1)*nlen
|
|
jb=ja+nlen-1
|
|
call pctile(s(ja),nlen,npct,base) !Find lowest npct of points
|
|
do i=ja,jb
|
|
if(s(i).le.base) then
|
|
if (k.lt.1000) k=k+1 !Save all "lower envelope" points
|
|
x(k)=i-i0
|
|
y(k)=s(i)
|
|
endif
|
|
enddo
|
|
enddo
|
|
kz=k
|
|
a=0.
|
|
call polyfit(x,y,y,kz,nterms,0,a,chisqr) !Fit a low-order polynomial
|
|
do i=ia,ib
|
|
t=i-i0
|
|
sbase(i)=a(1)+t*(a(2)+t*(a(3)+t*(a(4)+t*(a(5))))) + 0.65
|
|
! write(51,3051) i*df,s(i),sbase(i)
|
|
!3051 format(3f12.3)
|
|
enddo
|
|
|
|
return
|
|
end subroutine baselinejs8
|