WSJT-X/lib/fsk4hf/baseline.f90
Bill Somerville 2a87df0338 Merged from trunk:
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r8016 | k9an | 2017-08-09 16:22:54 +0100 (Wed, 09 Aug 2017) | 1 line

Remove call to jtmsg.
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r8017 | k9an | 2017-08-09 16:52:52 +0100 (Wed, 09 Aug 2017) | 1 line

Bring a simulation tool up to date.
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r8022 | k9an | 2017-08-13 02:35:13 +0100 (Sun, 13 Aug 2017) | 1 line

Improve efficiency of OSD by a factor of 5 to 10 for norder=2 and
3. Use norder=2 for wideband multi-decoding, norder=3 near nfqso and
nftx.
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r8026 | k9an | 2017-08-14 16:00:48 +0100 (Mon, 14 Aug 2017) | 1 line

Make default MSK144 amplitude polynomial flat.
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r8029 | k1jt | 2017-08-19 14:07:27 +0100 (Sat, 19 Aug 2017) | 1 line

Edit the advice displayed by F5.
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r8030 | k1jt | 2017-08-19 23:34:26 +0100 (Sat, 19 Aug 2017) | 1 line

Fix a typo.
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r8031 | k9an | 2017-08-22 01:14:51 +0100 (Tue, 22 Aug 2017) | 1 line

1. Improvements to the OSD to allow deeper wideband decoding.
2. Add a third decoding pass.
3. Change symbol metric from max-log to max-amplitude.
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r8032 | k9an | 2017-08-22 01:17:23 +0100 (Tue, 22 Aug 2017) | 1 line

Delete unused array.
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r8033 | k9an | 2017-08-22 01:21:59 +0100 (Tue, 22 Aug 2017) | 1 line

More cleanup.
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r8034 | k1jt | 2017-08-24 14:38:47 +0100 (Thu, 24 Aug 2017) | 1 line

Possible pseudo-code for DXpedition auto-sequencing.
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r8035 | k1jt | 2017-08-25 17:59:58 +0100 (Fri, 25 Aug 2017) | 4 lines

Use the most recently edited "CQ xx: message in Tx6 as a template for
subsequent regenerations.

This means that "CQ DX", "CQ VT", etc., will be presistent until
changed back.

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r8036 | k1jt | 2017-08-26 17:30:47 +0100 (Sat, 26 Aug 2017) | 1 line

Use a baseline-fitting procedure to improve S/N estimates for FT8.
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r8037 | k1jt | 2017-08-27 13:26:37 +0100 (Sun, 27 Aug 2017) | 1 line

Fix the 'Start=0 ==> S/N = -24 dB' problem.
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r8038 | k1jt | 2017-08-27 14:11:56 +0100 (Sun, 27 Aug 2017) | 1 line

Change magic 36 back to 37; does this break something else?
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r8039 | k1jt | 2017-08-28 15:32:14 +0100 (Mon, 28 Aug 2017) | 2 lines

Correct the behavior of FT8 in "NA VHF Contest mode".

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r8040 | k9an | 2017-08-28 22:09:44 +0100 (Mon, 28 Aug 2017) | 1 line

Fix a potential array bounds issue in osd174.f90.
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r8043 | bsomervi | 2017-08-29 04:20:37 +0100 (Tue, 29 Aug 2017) | 1 line

Update AD1C cty.dat database to 14th Aug 2017 big CTY.DAT
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r8044 | bsomervi | 2017-08-29 04:20:51 +0100 (Tue, 29 Aug 2017) | 1 line

Basic fix of auto sequencing with free text 73 messages, more to come
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r8045 | bsomervi | 2017-08-29 04:46:32 +0100 (Tue, 29 Aug 2017) | 1 line

Ensure that auto Tx is disabled when stop Tx on 73 isn't enabled and
DX call is cleared
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r8046 | k1jt | 2017-08-29 15:01:55 +0100 (Tue, 29 Aug 2017) | 2 lines

Update text in User Guide related to *NA VHF Contest Mode*.

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r8047 | bsomervi | 2017-08-30 03:27:57 +0100 (Wed, 30 Aug 2017) | 7 lines

Fix some signoff issues with auto-sequencing

73 messages from other QSOs on  frequency should now be ignored rather
than being processed.

Also some  long overdue refactoring  and tidying of  non-idiomatic C++
code in the logbook directory.
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r8048 | bsomervi | 2017-08-30 14:20:39 +0100 (Wed, 30 Aug 2017) | 1 line

Make 73 and RR73 matching of incoming messages for exact while words
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r8049 | k1jt | 2017-08-30 18:06:49 +0100 (Wed, 30 Aug 2017) | 1 line

Updates to User Guide.
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git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx-1.8@8050 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2017-08-31 00:41:52 +00:00

49 lines
1.3 KiB
Fortran

subroutine baseline(s,nfa,nfb,sbase)
! Fit baseline to spectrum (for FT8)
! Input: s(npts) Linear scale in power
! Output: sbase(npts) Baseline
implicit real*8 (a-h,o-z)
real*4 s(1920)
real*4 sbase(1920)
real*4 base
real*8 x(1000),y(1000),a(5)
data nseg/10/,npct/10/
df=12000.0/3840.0 !3.125 Hz
ia=max(1,nint(nfa/df))
ib=nint(nfb/df)
do i=ia,ib
s(i)=10.0*log10(s(i)) !Convert to dB scale
enddo
nterms=5
nlen=(ib-ia+1)/nseg !Length of test segment
i0=(ib-ia+1)/2 !Midpoint
k=0
do n=1,nseg !Loop over all segments
ja=ia + (n-1)*nlen
jb=ja+nlen-1
call pctile(s(ja),nlen,npct,base) !Find lowest npct of points
do i=ja,jb
if(s(i).le.base) then
if (k.lt.1000) k=k+1 !Save all "lower envelope" points
x(k)=i-i0
y(k)=s(i)
endif
enddo
enddo
kz=k
a=0.
call polyfit(x,y,y,kz,nterms,0,a,chisqr) !Fit a low-order polynomial
do i=ia,ib
t=i-i0
sbase(i)=a(1)+t*(a(2)+t*(a(3)+t*(a(4)+t*(a(5))))) + 0.65
! write(51,3051) i*df,s(i),sbase(i)
!3051 format(3f12.3)
enddo
return
end subroutine baseline