mirror of https://github.com/saitohirga/WSJT-X.git
151 lines
4.2 KiB
Fortran
151 lines
4.2 KiB
Fortran
subroutine mtdecode(dat,jz,s2,nchan,nz,MinSigdB,MinWidth,
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+ NQRN,DFTolerance,istart,pick,MouseButton,NSaveCum,
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+ cfile6,ps0)
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C Decode Multi-Tone FSK441 mesages.
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real dat(jz) !Raw audio data
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real s2(nchan,nz) !2d spectrum of data
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integer NQRN
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integer DFTolerance
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logical pick
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character*6 cfile6,cf*1
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real sigdb(3100) !Detected signal in dB, sampled at 20 ms
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real work(3100)
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integer indx(3100)
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real pingdat(3,100)
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real ps(128)
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real ps0(128)
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character msg*40,msg3*3
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character*90 line
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common/ccom/nline,tping(100),line(100)
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! slim=10.0*log10(10.0**(0.1*MinSigdB)+1.0)
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slim=MinSigdB
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wmin=0.001*MinWidth * (19.95/20.0)
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nf1=-DFTolerance
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nf2=DFTolerance
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msg3=' '
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nq=64
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dt=1.0/11025.0
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df=11025.0/256.0
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C Find signal power at suitable intervals to search for pings.
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istep=221
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dtbuf=istep/11025.
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do n=1,nz
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s=0.
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ib=n*istep
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ia=ib-istep+1
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do i=ia,ib
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s=s+dat(i)**2
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enddo
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sigdb(n)=s/istep
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enddo
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!#####################################################################
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if(.not.pick) then
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! Remove initial transient from sigdb
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call indexx(nz,sigdb,indx)
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imax=0
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do i=1,50
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if(indx(i).gt.50) go to 10
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imax=max(imax,indx(i))
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enddo
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10 do i=1,50
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if(indx(nz+1-i).gt.50) go to 20
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imax=max(imax,indx(nz+1-i))
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enddo
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20 imax=imax+6 !Safety margin
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base1=sigdb(indx(nz/2))
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do i=1,imax
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sigdb(i)=base1
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enddo
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endif
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!##################################################################
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call smooth(sigdb,nz)
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C Remove baseline and one dB for good measure.
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call pctile (sigdb,work,nz,50,base1)
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do i=1,nz
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sigdb(i)=dB(sigdb(i)/base1) - 1.0
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enddo
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call ping(sigdb,nz,dtbuf,slim,wmin,pingdat,nping)
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C If this is a "mouse pick", force a psuedo-ping at the center of
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C the data.
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if(pick) then
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if(nping.le.99) nping=nping+1
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pingdat(1,nping)=0.5*jz*dt
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pingdat(2,nping)=0.16
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pingdat(3,nping)=1.0
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endif
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bigpeak=0.
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do iping=1,nping
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C Find starting place and length of data to be analyzed:
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tstart=pingdat(1,iping)
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width=pingdat(2,iping)
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peak=pingdat(3,iping)
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mswidth=10*nint(100.0*width)
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jj=(tstart-0.02)/dt
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if(jj.lt.1) jj=1
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jjz=nint((width+0.02)/dt)+1
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jjz=min(jjz,jz+1-jj)
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C Compute average spectrum of this ping.
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call spec441(dat(jj),jjz,ps,f0)
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C Decode the message.
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msg=' '
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call longx(dat(jj),jjz,ps,DFTolerance,noffset,msg,
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+ msglen,bauderr,MouseButton)
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qrnlimit=4.4*1.5**(5.0-NQRN)
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if(NQRN.eq.0) qrnlimit=99.
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if(msglen.eq.0) go to 100
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C Assemble a signal report:
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nwidth=0
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if(width.ge.0.04) nwidth=1 !These might depend on NSPD
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if(width.ge.0.12) nwidth=2
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if(width.gt.1.00) nwidth=3
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nstrength=6
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if(peak.ge.11.0) nstrength=7
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if(peak.ge.17.0) nstrength=8
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if(peak.ge.23.0) nstrength=9
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! if(peak.gt.5.0 .and.mswidth.ge.100) then
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! call specsq(dat(jj),jjz,DFTolerance,0,noffset2)
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! noffset=noffset2
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! endif
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C Discard this ping if DF outside tolerance limits or bauderr too big.
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C (However, if the ping was mouse-picked, proceed anyway.)
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if(.not.pick .and. ((noffset.lt.nf1 .or. noffset.gt.nf2) .or.
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+ (abs(bauderr).gt.qrnlimit))) goto 100
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C If it's the best ping yet, save the spectrum:
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if(peak.gt.bigpeak) then
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bigpeak=peak
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do i=1,128
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ps0(i)=ps(i)
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enddo
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endif
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tstart=tstart + dt*(istart-1)
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cf=' '
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if(nline.le.99) nline=nline+1
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tping(nline)=tstart
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snr=10.0*log10(10.0**(0.1*peak)-1.0)
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write(line(nline),1050) cfile6,tstart,mswidth,int(peak),
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+ nwidth,nstrength,noffset,msg3,msg,cf
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1050 format(a6,f5.1,i5,i3,1x,2i1,i5,1x,a3,1x,a40,1x,a1)
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100 enddo
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return
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end
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