subroutine symspecx(k,nsps,ndiskdat,nb,nbslider,pxdb,s,nkhz,ihsym, & nzap,slimit,lstrong) ! k pointer to the most recent new data ! 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) ! pxdb power (0-60 dB) ! s spectrum for waterfall display ! nkhz integer kHz portion of center frequency, e.g., 125 for 144.125 ! ihsym index number of this half-symbol (1-322) ! nzap number of samples zero'ed by noise blanker parameter (NMAX=1800*12000) !Total sample intervals per 30 minutes parameter (NSMAX=4400) !Max length of saved spectra parameter (MAXFFT=262144) !Max length of FFTs integer*2 id2 real*8 ts,hsym real*8 fcenter common/jt8com/id2(NMAX),ss(184,NSMAX),savg(NSMAX),fcenter,nutc,junk(20) real*4 s(NSMAX) real x(MAXFFT) complex cx(0:MAXFFT/2) equivalence (x,cx) data rms/999.0/,k0/99999999/,ntrperiod0/0/ save nfft=nsps hsym=nsps/2 if(k.gt.NMAX) go to 999 if(k.lt.nfft) then ihsym=0 go to 999 !Wait for enough samples to start endif if(k.lt.k0) then ts=1.d0 - hsym savg=0. ihsym=0 k1=0 if(ndiskdat.eq.0) id2(k+1)=0. !### Should not be needed ??? ### endif k0=k nzap=0 sigmas=1.5*(10.0**(0.01*nbslider)) + 0.7 peaklimit=sigmas*max(10.0,rms) faclim=3.0 ts=ts+hsym ja=ts !Index of first sample jb=ja+nfft-1 !Last sample i=0 sq=0. do j=ja,jb !Copy data into cx, cy i=i+1 x(i)=id2(j) sq=sq + x(i)*x(i) enddo rms=sqrt(sq/nfft) pxdb=0. if(rms.gt.1.0) pxdb=20.0*log10(rms) if(pxdb.gt.60.0) pxdb=60.0 ihsym=ihsym+1 call four2a(x,nfft,1,-1,0) !Forward FFT of symbol length df=12000.0/nfft nzh=min(nint(500.0/df),2200) nz=2*nzh i0=nint(1500.0/df) - nzh rewind 71 do i=1,nz sx=real(cx(i0+i))**2 + aimag(cx(i0+i))**2 sx=1.e-8*sx s(i)=sx savg(i)=savg(i) + sx if(ihsym.le.184) ss(ihsym,i)=sx write(71,3001) (i0+i-1)*df,savg(i),db(savg(i)) 3001 format(f12.6,2f12.3) enddo flush(71) nkhz=100 999 return end subroutine symspecx