mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-18 10:01:57 -05:00
600c3e228c
Update the User's Guide. git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@3477 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
114 lines
3.0 KiB
Fortran
114 lines
3.0 KiB
Fortran
subroutine symspec(k,ntrperiod,nsps,ingain,slope,pxdb,s,df3,ihsym,npts8)
|
|
|
|
! Input:
|
|
! k pointer to the most recent new data
|
|
! ntrperiod T/R sequence length, minutes
|
|
! nsps samples per symbol, at 12000 Hz
|
|
! ndiskdat 0/1 to indicate if data from disk
|
|
! nb 0/1 status of noise blanker (off/on)
|
|
! nbslider NB setting, 0-100
|
|
|
|
! Output:
|
|
! pxdb power (0-60 dB)
|
|
! s() current spectrum for waterfall display
|
|
! ihsym index number of this half-symbol (1-184)
|
|
|
|
! jt9com
|
|
! ss() JT9 symbol spectra at half-symbol steps
|
|
! savg() average spectra for waterfall display
|
|
|
|
include 'constants.f90'
|
|
real*4 w3(MAXFFT3)
|
|
real*4 s(NSMAX)
|
|
real*4 scale(NSMAX)
|
|
real*4 ssum(NSMAX)
|
|
real*4 xc(0:MAXFFT3-1)
|
|
complex cx(0:MAXFFT3/2)
|
|
integer*2 id2
|
|
common/jt9com/ss(184,NSMAX),savg(NSMAX),id2(NMAX),nutc,ndiskdat, &
|
|
ntr,mousefqso,newdat,nfa,nfb,ntol,kin,nzhsym,nsynced,ndecoded
|
|
data rms/999.0/,k0/99999999/,nfft3z/0/,slope0/0.0/
|
|
equivalence (xc,cx)
|
|
save
|
|
|
|
if(ntrperiod.eq.-999) stop !Silence compiler warning
|
|
nfft3=16384 !df=12000.0/16384 = 0.732422
|
|
jstep=nsps/2 !Step size = half-symbol in id2()
|
|
if(k.gt.NMAX) go to 900
|
|
if(k.lt.2048) then !(2048 was nfft3) (Any need for this ???)
|
|
ihsym=0
|
|
go to 900 !Wait for enough samples to start
|
|
endif
|
|
|
|
if(nfft3.ne.nfft3z .or. slope.ne.slope0) then !New nfft3, compute window
|
|
pi=4.0*atan(1.0)
|
|
do i=1,nfft3
|
|
w3(i)=2.0*(sin(i*pi/nfft3))**2 !Window for nfft3 spectrum
|
|
enddo
|
|
nfft3z=nfft3
|
|
nh=NSMAX/2
|
|
do i=1,NSMAX
|
|
x=slope*float(i)/nh - 1.0 + 2.6
|
|
scale(i)=10.0**x
|
|
enddo
|
|
slope0=slope
|
|
endif
|
|
|
|
if(k.lt.k0) then !Start a new data block
|
|
ja=0
|
|
ssum=0.
|
|
ihsym=0
|
|
if(ndiskdat.eq.0) id2(k+1:)=0 !Needed to prevent "ghosts". Not sure why.
|
|
endif
|
|
gain=10.0**(0.05*ingain)
|
|
sq=0.
|
|
do i=k0+1,k
|
|
x1=id2(i)
|
|
sq=sq + x1*x1
|
|
enddo
|
|
sq=sq * gain**2
|
|
rms=sqrt(sq/(k-k0))
|
|
pxdb=0.
|
|
if(rms.gt.0.0) pxdb=20.0*log10(rms)
|
|
if(pxdb.gt.60.0) pxdb=60.0
|
|
|
|
|
|
k0=k
|
|
ja=ja+jstep !Index of first sample
|
|
|
|
fac0=0.1
|
|
do i=0,nfft3-1 !Copy data into cx
|
|
j=ja+i-(nfft3-1)
|
|
xc(i)=0.
|
|
if(j.ge.1) xc(i)=fac0*id2(j)
|
|
enddo
|
|
|
|
if(ihsym.lt.184) ihsym=ihsym+1
|
|
|
|
xc(0:nfft3-1)=w3(1:nfft3)*xc(0:nfft3-1) !Apply window w3
|
|
call four2a(xc,nfft3,1,-1,0) !Real-to-complex FFT
|
|
|
|
n=min(184,ihsym)
|
|
df3=12000.0/nfft3 !JT9-1: 0.732 Hz = 0.42 * tone spacing
|
|
! i0=nint(1000.0/df3)
|
|
i0=0
|
|
iz=min(NSMAX,nint(5000.0/df3))
|
|
fac=(1.0/nfft3)**2
|
|
do i=1,iz
|
|
j=i0+i-1
|
|
if(j.lt.0) j=j+nfft3
|
|
sx=fac*(real(cx(j))**2 + aimag(cx(j))**2)
|
|
ss(n,i)=sx
|
|
ssum(i)=ssum(i) + sx
|
|
s(i)=gain*sx
|
|
enddo
|
|
|
|
! s=0.05*s/ref
|
|
s=scale*s
|
|
savg=scale*ssum/ihsym
|
|
|
|
900 npts8=k/8
|
|
|
|
return
|
|
end subroutine symspec
|