Add LF/MF noise blanker capability for FST240 and FST240W.

CMakeLists.txt

@@ -396,6 +396,7 @@ set (wsjt_FSRCS
   lib/badmsg.f90
   lib/ft8/baseline.f90
   lib/ft4/ft4_baseline.f90
+  lib/blanker.f90
   lib/bpdecode40.f90
   lib/bpdecode128_90.f90
   lib/ft8/bpdecode174_91.f90

lib/blanker.f90

@@ -0,0 +1,52 @@
+subroutine blanker(iwave,nz,dwell_time,fblank,npct)
+
+  integer*2 iwave(nz)
+  integer hist(0:32768)
+  real dwell_time                 !Blanking dwell time (s)
+  real fblank                     !Fraction of points to be blanked
+  data ncall/0/,thresh/0.0/,fblanked/0.0/
+  save ncall,thresh,fblanked
+
+  ncall=ncall+1  
+  ndropmax=nint(1.0 + dwell_time*12000.0)
+  hist=0
+  do i=1,nz
+     n=abs(iwave(i))
+     hist(n)=hist(n)+1
+  enddo
+  n=0
+  do i=32768,0,-1
+     n=n+hist(i)
+     if(n.ge.nint(nz*fblank/ndropmax)) exit
+  enddo
+  thresh=thresh + 0.01*(i-thresh)
+  if(ncall.eq.1) thresh=i
+  nthresh=nint(thresh)
+  ndrop=0
+  ndropped=0
+     
+  do i=1,nz
+     i0=iwave(i)
+     if(ndrop.gt.0) then
+        iwave(i)=0
+        ndropped=ndropped+1
+        ndrop=ndrop-1
+        cycle
+     endif
+
+! Start to apply blanking
+     if(abs(iwave(i)).gt.nthresh) then
+        iwave(i)=0
+        ndropped=ndropped+1
+        ndrop=ndropmax
+     endif
+  enddo
+
+  fblanked=fblanked + 0.1*(float(ndropped)/nz - fblanked)
+  if(ncall.eq.1) fblanked=float(ndropped)/nz
+  npct=nint(100.0*fblanked)
+!  if(mod(ncall,4).eq.0) write(*,3001) thresh,dwell_time,fblank,fblanked,npct
+!3001 format(f8.1,f8.4,f6.2,f7.3,i6)
+
+  return
+end subroutine blanker

lib/fst240_decode.f90

@@ -78,6 +78,8 @@ contains
       data first/.true./
       save first,apbits,nappasses,naptypes,mycall0,hiscall0
 
+!      call blanker(iwave,ntrperiod*12000,0.0,0.2)
+      
       this%callback => callback
 
       dxcall13=hiscall   ! initialize for use in packjt77
@@ -788,7 +790,7 @@ contains
          iploc=ia+im(1)-1                         !Index of CCF peak
          pval=s2(iploc)                           !Peak value
          if(pval.lt.minsync) exit
-         if(s2(iploc).gt.thresh) then             !Is this a possible candidate?
+         if(s2(iploc).gt.minsync) then            !Is this a possible candidate?
             do i=-3,+3                            !Remove 0.9 of a model CCF at
                k=iploc+2*hmod*i                   !this frequency from s2()
                if(k.ge.ia .and. k.le.ib) then
@@ -803,5 +805,5 @@ contains
 
       return
    end subroutine get_candidates_fst240
-
+ 
 end module fst240_decode

lib/symspec.f90

@@ -1,5 +1,5 @@
 subroutine symspec(shared_data,k,TRperiod,nsps,ingain,bLowSidelobes,    &
-     nminw,pxdb,s,df3,ihsym,npts8,pxdbmax)
+     nminw,pxdb,s,df3,ihsym,npts8,pxdbmax,bblank,npct)
 
 ! Input:
 !  k              pointer to the most recent new data
@@ -7,8 +7,6 @@ subroutine symspec(shared_data,k,TRperiod,nsps,ingain,bLowSidelobes,    &
 !  nsps           samples per symbol, at 12000 Hz
 !  bLowSidelobes  true to use windowed FFTs
 !  ndiskdat       0/1 to indicate if data from disk
-!  nb             0/1 status of noise blanker (off/on)
-!  nbslider       NB setting, 0-100
 
 ! Output:
 !  pxdb      raw power (0-90 dB)
@@ -31,7 +29,7 @@ subroutine symspec(shared_data,k,TRperiod,nsps,ingain,bLowSidelobes,    &
   real*4 tmp(NSMAX)
   complex cx(0:MAXFFT3/2)
   integer nch(7)
-  logical*1 bLowSidelobes
+  logical*1 bLowSidelobes,bblank
 
   common/spectra/syellow(NSMAX),ref(0:3456),filter(0:3456)
   data k0/99999999/,nfft3z/0/
@@ -65,6 +63,12 @@ subroutine symspec(shared_data,k,TRperiod,nsps,ingain,bLowSidelobes,    &
   gain=10.0**(0.1*ingain)
   sq=0.
   pxmax=0.;
+
+  dwell_time=0.0001
+  fblank=0.15
+  if(k.gt.k0 .and. bblank) call blanker(shared_data%id2(k0+1:k),  &
+       k-k0,dwell_time,fblank,npct)
+
   do i=k0+1,k
      x1=shared_data%id2(i)
      if (abs(x1).gt.pxmax) pxmax = abs(x1);

widgets/mainwindow.cpp

@@ -91,7 +91,7 @@ extern "C" {
   //----------------------------------------------------- C and Fortran routines
   void symspec_(struct dec_data *, int* k, double* trperiod, int* nsps, int* ingain,
                 bool* bLowSidelobes, int* minw, float* px, float s[], float* df3,
-                int* nhsym, int* npts8, float *m_pxmax);
+                int* nhsym, int* npts8, float *m_pxmax, bool *bblank, int* npct);
 
   void hspec_(short int d2[], int* k, int* nutc0, int* ntrperiod, int* nrxfreq, int* ntol,
               bool* bmsk144, bool* btrain, double const pcoeffs[], int* ingain,
@@ -1132,6 +1132,8 @@ void MainWindow::writeSettings()
   m_settings->setValue ("FT8AP", ui->actionEnable_AP_FT8->isChecked ());
   m_settings->setValue ("JT65AP", ui->actionEnable_AP_JT65->isChecked ());
   m_settings->setValue("SplitterState",ui->splitter->saveState());
+  m_settings->setValue("Blanker",ui->cbNB->isChecked());
+
   {
     QList<QVariant> coeffs;     // suitable for QSettings
     for (auto const& coeff : m_phaseEqCoefficients)
@@ -1231,6 +1233,7 @@ void MainWindow::readSettings()
   ui->actionEnable_AP_FT8->setChecked (m_settings->value ("FT8AP", false).toBool());
   ui->actionEnable_AP_JT65->setChecked (m_settings->value ("JT65AP", false).toBool());
   ui->splitter->restoreState(m_settings->value("SplitterState").toByteArray());
+  ui->cbNB->setChecked(m_settings->value("Blanker",false).toBool());
   {
     auto const& coeffs = m_settings->value ("PhaseEqualizationCoefficients"
                                             , QList<QVariant> {0., 0., 0., 0., 0.}).toList ();
@@ -1389,8 +1392,13 @@ void MainWindow::dataSink(qint64 frames)
   if(m_bFastMode) nsps=6912;
   int nsmo=m_wideGraph->smoothYellow()-1;
   bool bLowSidelobes=m_config.lowSidelobes();
+  bool bblank=ui->cbNB->isChecked() and m_mode.startsWith("FST240");
+  int npct=0;
   symspec_(&dec_data,&k,&m_TRperiod,&nsps,&m_inGain,&bLowSidelobes,&nsmo,&m_px,s,
-           &m_df3,&m_ihsym,&m_npts8,&m_pxmax);
+           &m_df3,&m_ihsym,&m_npts8,&m_pxmax,&bblank,&npct);
+  QString t=" ";
+  if(bblank) t=QString::number(npct);
+      ui->labNpct->setText(t);
   if(m_mode=="WSPR" or m_mode=="FST240W") wspr_downsample_(dec_data.d2,&k);
   if(m_ihsym <=0) return;
   if(ui) ui->signal_meter_widget->setValue(m_px,m_pxmax); // Update thermometer
@@ -4079,7 +4087,6 @@ void MainWindow::guiUpdate()
 
 //Once per second:
   if(nsec != m_sec0) {
-//    qDebug() << "onesec" << ui->RoundRobin->currentText();
     m_currentBand=m_config.bands()->find(m_freqNominal);
     if( SpecOp::HOUND == m_config.special_op_id() ) {
       qint32 tHound=QDateTime::currentMSecsSinceEpoch()/1000 - m_tAutoOn;
@@ -5806,6 +5813,10 @@ void MainWindow::displayWidgets(qint64 n)
   if(m_mode=="MSK144") b=SpecOp::EU_VHF==m_config.special_op_id();
   ui->sbSerialNumber->setVisible(b);
   m_lastCallsign.clear ();     // ensures Tx5 is updated for new modes
+  b=m_mode.startsWith("FST240");
+  ui->labNpct->setVisible(b);
+  ui->labNB->setVisible(b);
+  ui->cbNB->setVisible(b);
   genStdMsgs (m_rpt, true);
 }