Adaptive sample block size to match FFT sizes

This  change  corrects timing  discrepancies  on  the horizontal  fast
spectrum plot.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6780 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

Detector.cpp

@@ -11,22 +11,26 @@ extern "C" {
 }
 
 Detector::Detector (unsigned frameRate, unsigned periodLengthInSeconds,
-                    unsigned samplesPerFFT, unsigned downSampleFactor,
+                    unsigned downSampleFactor, QObject * parent)
-                    QObject * parent)
   : AudioDevice (parent)
   , m_frameRate (frameRate)
   , m_period (periodLengthInSeconds)
   , m_downSampleFactor (downSampleFactor)
-  , m_samplesPerFFT (samplesPerFFT)
+  , m_samplesPerFFT {max_buffer_size}
   , m_ns (999)
   , m_buffer ((downSampleFactor > 1) ?
-              new short [samplesPerFFT * downSampleFactor] : 0)
+              new short [max_buffer_size * downSampleFactor] : nullptr)
   , m_bufferPos (0)
 {
   (void)m_frameRate;            // quell compiler warning
   clear ();
 }
 
+void Detector::setBlockSize (unsigned n)
+{
+  m_samplesPerFFT = n;
+}
+
 bool Detector::reset ()
 {
   clear ();
@@ -83,7 +87,7 @@ qint64 Detector::writeData (char const * data, qint64 maxSize)
         if(m_bufferPos==m_samplesPerFFT*m_downSampleFactor) {
           qint32 framesToProcess (m_samplesPerFFT * m_downSampleFactor);
           qint32 framesAfterDownSample (m_samplesPerFFT);
-          if(framesToProcess==13824 and dec_data.params.kin>=0 and
+          if(m_downSampleFactor > 1 && dec_data.params.kin>=0 &&
              dec_data.params.kin < (NTMAX*12000 - framesAfterDownSample)) {
             fil4_(&m_buffer[0], &framesToProcess, &dec_data.d2[dec_data.params.kin],
                   &framesAfterDownSample);

Detector.hpp

@@ -22,12 +22,14 @@ public:
   //
   // the samplesPerFFT argument is the number after down sampling
   //
-  Detector (unsigned frameRate, unsigned periodLengthInSeconds, unsigned samplesPerFFT, unsigned downSampleFactor = 4u, QObject * parent = 0);
+  Detector (unsigned frameRate, unsigned periodLengthInSeconds, unsigned downSampleFactor = 4u, QObject * parent = 0);
 
-  Q_SIGNAL void framesWritten (qint64) const;
   void setPeriod(unsigned p) {m_period=p;}
   bool reset () override;
 
+  Q_SIGNAL void framesWritten (qint64) const;
+  Q_SLOT void setBlockSize (unsigned);
+
 protected:
   qint64 readData (char * /* data */, qint64 /* maxSize */) override
   {
@@ -45,6 +47,7 @@ private:
   unsigned m_downSampleFactor;
   qint32 m_samplesPerFFT;	// after any down sampling
   qint32 m_ns;
+  static size_t const max_buffer_size {7 * 512};
   QScopedArrayPointer<short> m_buffer; // de-interleaved sample buffer
   // big enough for all the
   // samples for one increment of

mainwindow.cpp

@@ -164,7 +164,8 @@ MainWindow::MainWindow(QDir const& temp_directory, bool multiple,
   m_lastDialFreq {0},
   m_callingFrequency {0},
   m_dialFreqRxWSPR {0},
-  m_detector {new Detector {RX_SAMPLE_RATE, NTMAX, 6912 / 2, downSampleFactor}},
+  m_detector {new Detector {RX_SAMPLE_RATE, NTMAX, downSampleFactor}},
+  m_FFTSize {6192 / 2},         // conservative value to avoid buffer overruns
   m_soundInput {new SoundInput},
   m_modulator {new Modulator {TX_SAMPLE_RATE, NTMAX}},
   m_soundOutput {new SoundOutput},
@@ -378,6 +379,7 @@ MainWindow::MainWindow(QDir const& temp_directory, bool multiple,
   connect (this, &MainWindow::finished, this, &MainWindow::close);
 
   // hook up the detector signals, slots and disposal
+  connect (this, &MainWindow::FFTSize, m_detector, &Detector::setBlockSize);
   connect(m_detector, &Detector::framesWritten, this, &MainWindow::dataSink);
   connect (&m_audioThread, &QThread::finished, m_detector, &QObject::deleteLater);
 
@@ -995,7 +997,7 @@ void MainWindow::dataSink(qint64 frames)
   }
 
   m_bUseRef=m_wideGraph->useRef();
-  refspectrum_(&dec_data.d2[k-3456],&m_bRefSpec,&m_bUseRef,c_fname,len);
+  refspectrum_(&dec_data.d2[k-m_nsps/2],&m_bRefSpec,&m_bUseRef,c_fname,len);
 
 // Get power, spectrum, and ihsym
   int trmin=m_TRperiod/60;
@@ -1219,7 +1221,7 @@ void MainWindow::fastSink(qint64 frames)
 
   decodeNow=false;
   m_k0=k;
-  if(m_diskData and m_k0 >= dec_data.params.kin-3456) decodeNow=true;
+  if(m_diskData and m_k0 >= dec_data.params.kin - 7 * 512) decodeNow=true;
   if(!m_diskData and m_tRemaining<0.35 and !m_bFastDecodeCalled) decodeNow=true;
 
   if(decodeNow) {
@@ -1824,8 +1826,7 @@ void MainWindow::on_actionDecode_remaining_files_in_directory_triggered()
 void MainWindow::diskDat()                                   //diskDat()
 {
   int k;
-//  int kstep=m_nsps/2;
+  int kstep=m_FFTSize;
-  int kstep=3456;
   m_diskData=true;
 
   float db=m_config.degrade();
@@ -3671,6 +3672,8 @@ void MainWindow::on_actionJT9_triggered()
   if(m_modeTx!="JT9") on_pbTxMode_clicked();
   statusChanged();
   m_nsps=6912;
+  m_FFTSize = m_nsps / 2;
+  Q_EMIT FFTSize (m_FFTSize);
   QString t1=(QString)QChar(short(m_nSubMode+65));
   m_hsymStop=173;
   if(m_config.decode_at_52s()) m_hsymStop=179;
@@ -3729,6 +3732,8 @@ void MainWindow::on_actionJTMSK_triggered()
   switch_mode (Modes::JTMSK);
   statusChanged();
   m_nsps=6;
+  m_FFTSize = 7 * 512;
+  Q_EMIT FFTSize (m_FFTSize);
   mode_label->setStyleSheet("QLabel{background-color: #ff6666}");
   mode_label->setText(m_mode);
   m_toneSpacing=0.0;
@@ -3770,6 +3775,8 @@ void MainWindow::on_actionMSK144_triggered()
   switch_mode (Modes::MSK144);
   statusChanged();
   m_nsps=6;
+  m_FFTSize = 7 * 512;
+  Q_EMIT FFTSize (m_FFTSize);
   mode_label->setStyleSheet("QLabel{background-color: #ff6666}");
   mode_label->setText(m_mode);
   m_toneSpacing=0.0;
@@ -3810,6 +3817,8 @@ void MainWindow::on_actionJT65_triggered()
   m_modulator->setPeriod(m_TRperiod); // TODO - not thread safe
   m_detector->setPeriod(m_TRperiod);   // TODO - not thread safe
   m_nsps=6912;                   //For symspec only
+  m_FFTSize = m_nsps / 2;
+  Q_EMIT FFTSize (m_FFTSize);
   m_hsymStop=173;
   if(m_config.decode_at_52s()) m_hsymStop=179;
   m_toneSpacing=0.0;
@@ -3860,6 +3869,8 @@ void MainWindow::on_actionJT9_JT65_triggered()
   m_modulator->setPeriod(m_TRperiod); // TODO - not thread safe
   m_detector->setPeriod(m_TRperiod);  // TODO - not thread safe
   m_nsps=6912;
+  m_FFTSize = m_nsps / 2;
+  Q_EMIT FFTSize (m_FFTSize);
   m_hsymStop=173;
   if(m_config.decode_at_52s()) m_hsymStop=179;
   m_toneSpacing=0.0;
@@ -3894,6 +3905,8 @@ void MainWindow::on_actionJT4_triggered()
   m_modulator->setPeriod(m_TRperiod); // TODO - not thread safe
   m_detector->setPeriod(m_TRperiod);  // TODO - not thread safe
   m_nsps=6912;                   //For symspec only
+  m_FFTSize = m_nsps / 2;
+  Q_EMIT FFTSize (m_FFTSize);
   m_hsymStop=179;
   m_toneSpacing=0.0;
   ui->actionJT4->setChecked(true);
@@ -3937,6 +3950,8 @@ void MainWindow::on_actionWSPR_2_triggered()
   m_modulator->setPeriod(m_TRperiod); // TODO - not thread safe
   m_detector->setPeriod(m_TRperiod);  // TODO - not thread safe
   m_nsps=6912;                   //For symspec only
+  m_FFTSize = m_nsps / 2;
+  Q_EMIT FFTSize (m_FFTSize);
   m_hsymStop=396;
   m_toneSpacing=12000.0/8192.0;
   mode_label->setStyleSheet("QLabel{background-color: #ff66ff}");
@@ -3970,6 +3985,8 @@ void MainWindow::on_actionEcho_triggered()
   m_modulator->setPeriod(m_TRperiod); // TODO - not thread safe
   m_detector->setPeriod(m_TRperiod);  // TODO - not thread safe
   m_nsps=6912;                   //For symspec only
+  m_FFTSize = m_nsps / 2;
+  Q_EMIT FFTSize (m_FFTSize);
   m_hsymStop=10;
   m_toneSpacing=1.0;
   switch_mode(Modes::Echo);
@@ -4001,6 +4018,8 @@ void MainWindow::on_actionISCAT_triggered()
   m_detector->setPeriod(m_TRperiod);
   m_wideGraph->setPeriod(m_TRperiod,m_nsps);
   m_nsps=6912;                   //For symspec only
+  m_FFTSize = m_nsps / 2;
+  Q_EMIT FFTSize (m_FFTSize);
   m_hsymStop=103;
   m_toneSpacing=11025.0/256.0;
   WSPR_config(false);
@@ -4699,6 +4718,8 @@ void MainWindow::transmit (double snr)
 
   if (m_modeTx == "JTMSK" or m_modeTx == "MSK144") {
     m_nsps=6;
+    m_FFTSize = 7 * 512;
+    Q_EMIT FFTSize (m_FFTSize);
     m_toneSpacing=6000.0/m_nsps;
     double f0=1000.0;
     int nsym;

mainwindow.h

@@ -260,6 +260,7 @@ private:
   Q_SIGNAL void suspendAudioInputStream () const;
   Q_SIGNAL void resumeAudioInputStream () const;
   Q_SIGNAL void startDetector (AudioDevice::Channel) const;
+  Q_SIGNAL void FFTSize (unsigned) const;
   Q_SIGNAL void detectorClose () const;
   Q_SIGNAL void finished () const;
   Q_SIGNAL void transmitFrequency (double) const;
@@ -308,6 +309,7 @@ private:
   Frequency  m_dialFreqRxWSPR;  // best guess at WSPR QRG
 
   Detector * m_detector;
+  unsigned m_FFTSize;
   SoundInput * m_soundInput;
   Modulator * m_modulator;
   SoundOutput * m_soundOutput;