ATV Modulator: full SSB support

debian/changelog

@@ -1,9 +1,15 @@
+sdrangel (3.3.1-1) unstable; urgency=medium
+
+  * ATV modulator: SSB support
+
+ -- Edouard Griffiths, F4EXB <f4exb06@gmail.com>  Thu, 16 Mar 2017 23:14:18 +0100
+
 sdrangel (3.3.0-1) unstable; urgency=medium
 
   * NFM demod: new discriminator and optional FM deviation based squelch
   * ATV modulator
 
- -- Edouard Griffiths, F4EXB <f4exb06@gmail.com>  Thu, 02 Mar 2017 23:14:18 +0100
+ -- Edouard Griffiths, F4EXB <f4exb06@gmail.com>  Wed, 15 Mar 2017 23:14:18 +0100
 
 sdrangel (3.2.0-1) unstable; urgency=medium
 

plugins/channeltx/modatv/atvmod.cpp

@@ -188,6 +188,11 @@ void ATVMod::modulateSample()
     	m_modSample.real(cos(m_modPhasor) * 29204.0f); // -1 dB
     	m_modSample.imag(sin(m_modPhasor) * 29204.0f);
     	break;
+    case ATVModulationLSB:
+    case ATVModulationUSB:
+        m_modSample = modulateSSB(t);
+        m_modSample *= 29204.0f;
+        break;
     case ATVModulationAM: // AM 90%
     default:
         m_modSample.real((t*1.8f + 0.1f) * 16384.0f); // modulate and scale zero frequency carrier
@@ -195,6 +200,25 @@ void ATVMod::modulateSample()
     }
 }
 
+Complex& ATVMod::modulateSSB(Real& sample)
+{
+    int n_out;
+    Complex ci(sample, 0.0f);
+    fftfilt::cmplx *filtered;
+
+    n_out = m_SSBFilter->runSSB(ci, &filtered, m_running.m_atvModulation == ATVModulationUSB);
+
+    if (n_out > 0)
+    {
+        memcpy((void *) m_SSBFilterBuffer, (const void *) filtered, n_out*sizeof(Complex));
+        m_SSBFilterBufferIndex = 0;
+    }
+
+    m_SSBFilterBufferIndex++;
+
+    return m_SSBFilterBuffer[m_SSBFilterBufferIndex-1];
+}
+
 void ATVMod::pullVideo(Real& sample)
 {
     int iLine = m_lineCount % m_nbLines2;

plugins/channeltx/modatv/atvmod.h

@@ -547,6 +547,7 @@ private:
     void pullVideo(Real& sample);
     void calculateLevel(Real& sample);
     void modulateSample();
+    Complex& modulateSSB(Real& sample);
     void applyStandard();
     void openImage(const QString& fileName);
     void openVideo(const QString& fileName);

plugins/channeltx/modatv/readme.md

@@ -34,6 +34,8 @@ The video signal can modulate the carrier in the following modes:
 
   - AM: Amplitude modulation. Modulation index is 90%.
   - FM: Frequency modulation. Excursion is half the bandwidth available given the channel sample rate. e.g. for 4 MS/s sample rate this is ±1 MHz (2 MHz total) 
+  - USB: SSB upper side band: video signal is transposed only in positive frequencies including DC component
+  - LSB: SSB lower side band: video signal is transposed only in megative frequencies excluding DC component
   
 <h3>6: RF bandwidth</h3>