subroutine qra64b(nutc,nqd,fcenter,nfcal,nfsample,ikhz,mousedf,ntol,xpol, & mycall_12,hiscall_12,hisgrid_6,mode64,nwrite_qra64) parameter (MAXFFT1=5376000) !56*96000 parameter (MAXFFT2=336000) !56*6000 (downsampled by 1/16) complex ca(MAXFFT1),cb(MAXFFT1) !FFTs of raw x,y data complex cx(0:MAXFFT2-1),cy(0:MAXFFT2-1) logical xpol real*8 fcenter character*12 mycall_12,hiscall_12 character*6 hisgrid_6 common/cacb/ca,cb data nzap/3/ open(17,file='red.dat',status='unknown') nfft1=MAXFFT1 nfft2=MAXFFT2 df=96000.0/NFFT1 if(nfsample.eq.95238) then nfft1=5120000 nfft2=322560 df=96000.0/nfft1 endif nh=nfft2/2 ikhz0=nint(1000.0*(fcenter-int(fcenter))) k0=((ikhz-ikhz0+48.0+1.27)*1000.0+nfcal)/df if(k0.lt.nh .or. k0.gt.nfft1-nh) go to 900 fac=1.0/nfft2 cx(0:nh)=ca(k0:k0+nh) cx(nh+1:nfft2-1)=ca(k0-nh+1:k0-1) cx=fac*cx if(xpol) then cy(0:nh)=cb(k0:k0+nh) cy(nh+1:nfft2-1)=cb(k0-nh+1:k0-1) cy=fac*cy endif ! Here cx and cy (if xpol) are frequency-domain data around the selected ! QSO frequency, taken from the full-length FFT computed in filbig(). ! Values for fsample, nfft1, nfft2, df, and the downsampled data rate ! are as follows: ! fSample nfft1 df nfft2 fDownSampled ! (Hz) (Hz) (Hz) !---------------------------------------------------- ! 96000 5376000 0.017857143 336000 6000.000 ! 95238 5120000 0.018601172 322560 5999.994 ! write(60) cx,cy,nutc,nqd,ikhz,mousedf,ntol,xpol,mycall_12, & ! hiscall_12,hisgrid_6 if(nzap.gt.0) call qra64zap(cx,cy,xpol,nzap) ! Transform back to time domain with sample rate 6000 Hz. call four2a(cx,nfft2,1,-1,1) call four2a(cy,nfft2,1,-1,1) call qra64c(cx,cy,nutc,nqd,ikhz,mousedf,ntol,xpol,mycall_12, & hiscall_12,hisgrid_6,mode64,nwrite_qra64) close(17) 900 return end subroutine qra64b