WSJT-X/lib/wav12.f90
2020-02-21 13:36:49 -05:00

50 lines
1.2 KiB
Fortran

subroutine wav12(d2,d1,npts,nbitsam2)
! Convert i*2 or i*1 data at 11025 Hz (from WSJT *.wav files)
! to i*2 data at 12000 Hz.
! Input: i*2 d2(npts) or i*1 d1(npts)
! i*2 nbitsam2 = 8 or 16 (bits per sample)
! Output: npts = (12000*npts)/11025
! i*2 d2(npts)
parameter (NZ11=60*11025,NZ12=60*12000)
parameter (NFFT1=64*11025,NFFT2=64*12000)
integer*1 d1(NZ11)
integer*1 d1a(NZ11)
integer*1 i1
integer*2 i2
integer*2 d2(NZ12)
real x(NFFT2)
complex cx(0:NFFT2/2)
integer*2 nbitsam2
equivalence (x,cx),(i1,i2)
jz=min(NZ11,npts)
if(nbitsam2.eq.8) then
jz=min(NZ11,npts)
d1a(1:jz)=d1(1:jz) !d1 and d2 may be same array in calling prog
do i=1,jz !Move data from d1a into d2
i2=0
i1=d1a(i)
d2(i)=10*(i2-128)
enddo
endif
x(1:jz)=d2(1:jz)
x(jz+1:)=0.0
call four2a(cx,nfft1,1,-1,0) !Forwarxd FFT, r2c
cx(nfft1/2:)=0.0
call four2a(cx,nfft2,1,1,-1) !Inverse FFT, c2r
npts=jz*12000.0/11025.0
fac=1.e-6
! if(nbitsam2.eq.16) fac=3.e-6
x=fac*x
d2(1:npts)=nint(x(1:npts))
if(npts.lt.NZ12) d2(npts+1:NZ12)=0
return
end subroutine wav12