[Discuss-gnuradio] what does multi-tasker?

[Suvda Myagmar]

I've got a code for FM transmitter, but not familiar with some of the 
classes used there. Since the code is based on gnuradio 0.9, I can't find 
the source code for this earlier version. Does anyone know what VrMultiTask 
does? Also is NWO_Connect is the same as the connect method of flow_graph 
in the latest version? The code is below. Thanks

-Suvda

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#include <VrSource.h>
#include <VrConnect.h>
#include <VrMultiTask.h>
#include <VrSigSource.h>
#include <VrGUI.h>

#include <GrAudioSink.h>
#include <GrFileSink.h>
#include <GrFFTSink.h>

#include "etgQuarterMixer.h"
#include "etgFrequencyModulator.h"
#include "xmithelper.h"

#if HAVE_KNOBBY
#include <knobby.h>
/*
  Knobby is a homebrew library that allows one to use a Griffin Powermate dial
  to control a parameter. If knobby is availible, then the powermate will 
control the
  modulation index. If not, don't worry about it. :)
*/
#else
bool knob_control(void (*pcallback)(float), float p_init=0, float 
p_inc=1){return false;}
void knob_update(){}
#endif




namespace {
   VrSigProc* input=0;
   etgFrequencyModulator<float>* modulator;
   etgQuarterMixer<VrComplex,VrComplex>* carrier;
   VrSink<VrComplex>* out_IQ;
   VrMultiTask* mtasker;
   bool use_gui_p;

   VrGUI* guimain;
   VrSink<float>* inputfft;

   void knob_modindex(float param){
      modulator->SetModulationIndex(param);
      cout<<"Mod index = "<<param<<endl;
   }
}

namespace sdr {
   const int sampfreq = 48000;

   void SetupXmitter(float modindex, bool use_gui){
      use_gui_p = use_gui;


// etgFrequencyModulator is my experimental fm modulator. The
// single argument to the constructor should be the modulation index
      modulator=new etgFrequencyModulator<float>(modindex);

//etgQuarterMixer is a 1/4th sample rate complex mixer
      carrier=new etgQuarterMixer<VrComplex,VrComplex> (1);

// Outputs I and Q to the separate audio channels
// Keep amplitude within ~95% of max
      out_IQ = new GrAudioSink<VrComplex>(1.05,"/dev/dsp0");


      NWO_CONNECT(modulator, carrier);
      NWO_CONNECT(carrier,out_IQ);

      mtasker = new VrMultiTask ();
      mtasker->add (out_IQ);


// Construct the GUI - three fft's for each stage (signal, mod, demod)
      if (use_gui_p){
         VrGUILayout *horiz = 0;
         VrGUILayout *vert = 0;

         VrSink<float> *fft_sink1 = 0;
         VrSink<VrComplex> *fft_sink2 = 0,*fft_sink4 = 0;
         VrSink<float> *fft_sink3 = 0;

         int argc=0;
         char* argv[]={""};
         guimain = new VrGUI(argc, argv);
         horiz = guimain->top->horizontal();
         vert = horiz->vertical();

         // sink1 is source  output
         inputfft = new GrFFTSink<float>(vert, -40, 140, 1000);

         // sink2 is modulator output
         fft_sink2 = new GrFFTSink<VrComplex>(vert, -150, 50, 1000);



         NWO_CONNECT (carrier, fft_sink2);
         mtasker->add (inputfft);
         mtasker->add (fft_sink2);

      }




      knob_control(&knob_modindex,modindex,modindex/10);

   }



   void Update(){
      assert(input!=NULL);
      static bool isinit=false;
      if (!isinit){
         isinit=true;
         mtasker->start ();
         if (use_gui_p)
            guimain->start ();
        
      }

      if (use_gui_p)
         guimain->processEvents(10); //in ms
      mtasker->process();
      knob_update();
   }    

   void SetModIndex(float modindex){
      knob_modindex(modindex);
   }

   void SetSource(VrSigProc* src){
      assert(input==NULL);
      input=src;
      NWO_CONNECT(input,modulator);

      if (use_gui_p){
         NWO_CONNECT(src,inputfft);
      }
   }

   VrSigProc* GetSource() { return input;}
   VrSigProc* GetModulatedOut() {return modulator;}
   VrSigProc* GetCarrierOut(){ return carrier;}

   VrMultiTask* GetMultiTasker(){ return mtasker;}
}
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