mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-22 12:23:37 -05:00
2c17544f3f
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/WSJT/trunk@1 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
125 lines
2.6 KiB
Fortran
125 lines
2.6 KiB
Fortran
subroutine spec2d(data,jz,nstep,s2,nchan,nz,psavg0,sigma)
|
|
|
|
C Computes 2d spectrogram for FSK441 single-tone search and waterfall
|
|
C display.
|
|
|
|
parameter (NFFT=256)
|
|
parameter (NR=NFFT+2)
|
|
parameter (NH=NFFT/2)
|
|
parameter (NQ=NFFT/4)
|
|
|
|
real data(jz)
|
|
real s2(nchan,nz)
|
|
real x(NR)
|
|
real w1(7),w2(7)
|
|
real psavg(128)
|
|
real psavg0(128)
|
|
real ps2(128)
|
|
complex c(0:NH)
|
|
common/acom/a1,a2,a3,a4
|
|
common/fcom/s(3100),indx(3100)
|
|
equivalence (x,c)
|
|
save
|
|
|
|
df=11025.0/NFFT
|
|
|
|
C Compute the 2d spectrogram s2(nchan,nz). Note that in s2 the frequency
|
|
C bins are shifted down 5 bins from their natural positions.
|
|
|
|
call set(0.0,psavg,NH)
|
|
do n=1,nz
|
|
j=1 + (n-1)*nstep
|
|
call move(data(j),x,NFFT)
|
|
call xfft(x,NFFT)
|
|
|
|
sum=0.
|
|
do i=1,NQ
|
|
s2(i,n)=real(c(5+i))**2 + imag(c(5+i))**2
|
|
sum=sum+s2(i,n)
|
|
enddo
|
|
s(n)=sum/NQ
|
|
|
|
C Accumulate average spectrum for the whole file.
|
|
do i=1,nh
|
|
psavg0(i) = psavg0(i)+ real(c(i))**2 + imag(c(i))**2
|
|
enddo
|
|
enddo
|
|
|
|
C Normalize and save a copy of psavg0 for plotting. Roll off the
|
|
C spectrum at 300 and 3000 Hz.
|
|
do i=1,nh
|
|
psavg0(i)=3.e-5*psavg0(i)/nz
|
|
f=df*i
|
|
fac=1.0
|
|
if(f.lt.300.0) fac=f/300.0
|
|
if(f.gt.3000.0) fac=max(0.00333,(3300.0-f)/300.0)
|
|
psavg0(i)=(fac**2)*psavg0(i)
|
|
enddo
|
|
|
|
C Compute an average spectrum from the weakest 25% of time slices.
|
|
call indexx(nz,s,indx)
|
|
call zero(ps2,NQ)
|
|
do j=1,nz/4
|
|
k=indx(j)
|
|
do i=1,NQ
|
|
ps2(i+5)=ps2(i+5)+s2(i,k)
|
|
enddo
|
|
enddo
|
|
ps2(1)=ps2(5)
|
|
ps2(2)=ps2(5)
|
|
ps2(3)=ps2(5)
|
|
ps2(4)=ps2(5)
|
|
sum=0.
|
|
do i=6,59
|
|
sum=sum+ps2(i)
|
|
enddo
|
|
|
|
C Compute a smoothed spectrum without local peaks, and find its max.
|
|
smaxx=0.
|
|
do i=4,NQ
|
|
sum=0.
|
|
do k=1,7
|
|
w1(k)=ps2(i+k-4)
|
|
sum=sum+w1(k)
|
|
enddo
|
|
ave=sum/7.0
|
|
if(i.ge.14 .and. i.le.58) then
|
|
call pctile(w1,w2,7,50,base)
|
|
ave=0.25*(w2(1)+w2(2)+w2(3)+w2(4))
|
|
endif
|
|
psavg(i)=ave
|
|
smaxx=max(psavg(i),smaxx)
|
|
enddo
|
|
|
|
C Save scale factors for flattening spectra of pings.
|
|
a1=1.0
|
|
a2=psavg(nint(2*441/df))/psavg(nint(3*441/df))
|
|
a3=psavg(nint(2*441/df))/psavg(nint(4*441/df))
|
|
a4=psavg(nint(2*441/df))/psavg(nint(5*441/df))
|
|
afac=4.0/(a1+a2+a3+a4)
|
|
a1=afac*a1
|
|
a2=afac*a2
|
|
a3=afac*a3
|
|
a4=afac*a4
|
|
|
|
C Normalize 2D spectrum by the average based on weakest 25% of time
|
|
C slices, smoothed, and with local peaks removed.
|
|
|
|
do i=1,NQ
|
|
do j=1,nz
|
|
s2(i,j)=s2(i,j)/max(psavg(i+5),0.01*smaxx)
|
|
enddo
|
|
enddo
|
|
|
|
C Find average of active spectral region, over the whole file.
|
|
sum=0.
|
|
do i=9,52
|
|
do j=1,nz
|
|
sum=sum+s2(i,j)
|
|
enddo
|
|
enddo
|
|
sigma=sum/(44*nz)
|
|
|
|
return
|
|
end
|