Code cleanup and documentation.

This commit is contained in:
Joe Taylor 2020-10-09 13:16:25 -04:00
parent 8612398b02
commit a4ba64a5fa
2 changed files with 40 additions and 35 deletions

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@ -31,22 +31,32 @@ contains
subroutine decode(this,callback,iwave,nutc,ntrperiod,nsubmode,nfqso, & subroutine decode(this,callback,iwave,nutc,ntrperiod,nsubmode,nfqso, &
ntol,ndepth,mycall,hiscall,hisgrid) ntol,ndepth,mycall,hiscall,hisgrid)
! Decodes QRA65 signals
! Input: iwave Raw data, i*2
! nutc UTC for time-tagging the decode
! ntrperiod T/R sequence length (s)
! nsubmode Tone-spacing indicator, 0-4 for A-E
! nfqso Target signal frequency (Hz)
! ntol Search range around nfqso (Hz)
! ndepth Optional decoding level (???)
! Output: sent to the callback routine for display to user
use timer_module, only: timer use timer_module, only: timer
use packjt use packjt
use, intrinsic :: iso_c_binding use, intrinsic :: iso_c_binding
parameter (NMAX=300*12000) !### Needs to be 300*12000 ### parameter (NMAX=300*12000) !Max TRperiod is 300 s
class(qra65_decoder), intent(inout) :: this class(qra65_decoder), intent(inout) :: this
procedure(qra65_decode_callback) :: callback procedure(qra65_decode_callback) :: callback
character(len=12) :: mycall, hiscall character(len=12) :: mycall, hiscall !Used for AP decoding
character(len=6) :: hisgrid character(len=6) :: hisgrid
character*37 decoded character*37 decoded !Decoded message
integer*2 iwave(NMAX) !Raw data integer*2 iwave(NMAX) !Raw data
real dd(NMAX) !Raw data real dd(NMAX) !Raw data
integer dat4(12) integer dat4(12) !Decoded message as 12 6-bit integers
logical lapdx,ltext logical ltext
complex, allocatable :: c00(:) !Analytic signal, 6000 S/s complex, allocatable :: c00(:) !Analytic signal, 6000 Sa/s
complex, allocatable :: c0(:) !Analytic signal, 6000 S/s complex, allocatable :: c0(:) !Analytic signal, 6000 Sa/s
real, allocatable, save :: s3(:,:) !Symbol spectra real, allocatable, save :: s3(:,:) !Synchronized symbol spectra
real, allocatable, save :: s3a(:,:) !Symbol spectra for avg messages real, allocatable, save :: s3a(:,:) !Symbol spectra for avg messages
data nc1z/-1/,nc2z/-1/,ng2z/-1/,maxaptypez/-1/,nsubmodez/-1/ data nc1z/-1/,nc2z/-1/,ng2z/-1/,maxaptypez/-1/,nsubmodez/-1/
save nc1z,nc2z,ng2z,maxaptypez,nsave,nsubmodez save nc1z,nc2z,ng2z,maxaptypez,nsave,nsubmodez

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@ -1,19 +1,29 @@
subroutine sync_qra65(iwave,nmax,mode65,nsps,nfqso,ntol,xdt,f0,snr1) subroutine sync_qra65(iwave,nmax,mode65,nsps,nfqso,ntol,xdt,f0,snr1)
! Look for the sync vector in a QRA65 signal.
! Input: iwave(0:nmax-1) Raw data
! mode65 Tone spacing 1 2 4 8 16 (A-E)
! nsps Samples per symbol at 12000 Sa/s
! nfqso Target frequency (Hz)
! ntol Search range around nfqso (Hz)
! Output: xdt Time offset from nominal (s)
! f0 Frequency of sync tone
! snr1 Relative SNR of sync signal
parameter (NSTEP=4) !Quarter-symbol steps parameter (NSTEP=4) !Quarter-symbol steps
integer*2 iwave(0:nmax-1) !Raw data integer*2 iwave(0:nmax-1) !Raw data
integer isync(22) !Indices of sync symbols integer isync(22) !Indices of sync symbols
integer ijpk(2) !Indices i and j at peak of ccf integer ijpk(2) !Indices i and j at peak of ccf
real, allocatable :: s1(:,:) !Symbol spectra, quarter-symbol steps real, allocatable :: s1(:,:) !Symbol spectra, quarter-symbol steps
real sync(85) !sync vector real sync(85) !sync vector
real ccf(-64:64,-26:107) real ccf(-64:64,-26:107) !CCF(freq,time)
complex, allocatable :: c0(:) !Complex spectrum of symbol complex, allocatable :: c0(:) !Complex spectrum of symbol
data isync/1,9,12,13,15,22,23,26,27,33,35,38,46,50,55,60,62,66,69,74,76,85/ data isync/1,9,12,13,15,22,23,26,27,33,35,38,46,50,55,60,62,66,69,74,76,85/
data sync(1)/99.0/ data sync(1)/99.0/
save sync save sync
nfft=2*nsps nfft=2*nsps
df=12000.0/nfft df=12000.0/nfft !Freq resolution = 0.5*baud
istep=nsps/NSTEP istep=nsps/NSTEP
iz=5000.0/df !Uppermost frequency bin, at 5000 Hz iz=5000.0/df !Uppermost frequency bin, at 5000 Hz
txt=85.0*nsps/12000.0 txt=85.0*nsps/12000.0
@ -23,10 +33,10 @@ subroutine sync_qra65(iwave,nmax,mode65,nsps,nfqso,ntol,xdt,f0,snr1)
allocate(s1(iz,jz)) allocate(s1(iz,jz))
allocate(c0(0:nfft-1)) allocate(c0(0:nfft-1))
if(sync(1).eq.99.0) then if(sync(1).eq.99.0) then !Generate the sync vector
sync=-22.0/63.0 !Sync OFF sync=-22.0/63.0 !Sync tone OFF
do k=1,22 do k=1,22
sync(isync(k))=1.0 !Sync ON sync(isync(k))=1.0 !Sync tone ON
enddo enddo
endif endif
@ -46,27 +56,23 @@ subroutine sync_qra65(iwave,nmax,mode65,nsps,nfqso,ntol,xdt,f0,snr1)
do i=1,iz do i=1,iz
s1(i,j)=real(c0(i))**2 + aimag(c0(i))**2 s1(i,j)=real(c0(i))**2 + aimag(c0(i))**2
enddo enddo
! For large Doppler spreads, should we smooth the spectra here?
enddo enddo
i0=nint(nfqso/df) i0=nint(nfqso/df) !Target QSO frequency
call pctile(s1(i0-64:i0+192,1:jz),129*jz,40,base) call pctile(s1(i0-64:i0+192,1:jz),129*jz,40,base)
s1=s1/base s1=s1/base !Maybe should subtract 1.0 here?
s1max=20.0
! Apply AGC ! Apply fast AGC
s1max=20.0 !Empirical choice
do j=1,jz do j=1,jz
smax=maxval(s1(i0-64:i0+192,j)) smax=maxval(s1(i0-64:i0+192,j))
if(smax.gt.s1max) s1(i0-64:i0+192,j)=s1(i0-64:i0+192,j)*s1max/smax if(smax.gt.s1max) s1(i0-64:i0+192,j)=s1(i0-64:i0+192,j)*s1max/smax
enddo enddo
! do i=1,iz
! write(60,3060) i,i*df,sum(s1(i,1:jz))
!3060 format(i6,f10.3,e12.3)
! enddo
dt4=nsps/(NSTEP*12000.0) !1/4 of symbol duration dt4=nsps/(NSTEP*12000.0) !1/4 of symbol duration
j0=0.5/dt4 j0=0.5/dt4
if(nsps.ge.7680) j0=1.0/dt4 if(nsps.ge.7680) j0=1.0/dt4 !Nominal index for start of signal
ccf=0. ccf=0.
ia=min(64,nint(ntol/df)) ia=min(64,nint(ntol/df))
@ -85,23 +91,12 @@ subroutine sync_qra65(iwave,nmax,mode65,nsps,nfqso,ntol,xdt,f0,snr1)
enddo enddo
enddo enddo
! do i=-64,64
! write(61,3061) i,ccf(i,jpk)
!3061 format(i5,e12.3)
! enddo
! do j=lag1,lag2
! write(62,3061) j,ccf(ipk,j)
! enddo
ijpk=maxloc(ccf) ijpk=maxloc(ccf)
ipk=ijpk(1)-65 ipk=ijpk(1)-65
! jpk=ijpk(2)-16
jpk=ijpk(2)-27 jpk=ijpk(2)-27
f0=nfqso + ipk*df f0=nfqso + ipk*df
xdt=jpk*dt4 xdt=jpk*dt4
snr1=maxval(ccf)/22.0 snr1=maxval(ccf)/22.0
! write(*,3100) ipk,jpk,xdt,f0,snr1
!3100 format(2i5,f7.2,2f10.2)
return return
end subroutine sync_qra65 end subroutine sync_qra65