subroutine lpf1(dat,jz,nz,mousedf,mousedf2) parameter (NMAX=1024*1024) parameter (NMAXH=NMAX) real dat(jz),x(NMAX) complex c(0:NMAXH) equivalence (x,c) C Find FFT length xn=log(float(jz))/log(2.0) n=xn if((xn-n).gt.0.) n=n+1 nfft=2**n nh=nfft/2 C Load data into real array x; pad with zeros up to nfft. do i=1,jz x(i)=dat(i) enddo if(nfft.gt.jz) call zero(x(jz+1),nfft-jz) C Do the FFT call xfft(x,nfft) df=11025.0/nfft ia=70/df do i=0,ia c(i)=0. enddo ia=5000.0/df do i=ia,nh c(i)=0. enddo C See if frequency needs to be shifted: ndf=0 if(mousedf.lt.-600) ndf=-670 if(mousedf.gt.600) ndf=1000 if(mousedf.gt.1600) ndf=2000 if(mousedf.gt.2600) ndf=3000 if(ndf.ne.0) then C Shift frequency up or down by ndf Hz: i0=nint(ndf/df) if(i0.lt.0) then do i=nh,-i0,-1 c(i)=c(i+i0) enddo else do i=0,nh-i0 c(i)=c(i+i0) enddo endif endif mousedf2=mousedf-ndf !Adjust mousedf call four2a(c,nh,1,1,-1) !Return to time domain fac=1.0/nfft nz=jz/2 do i=1,nz dat(i)=fac*x(i) enddo return end