- added signal detection

git-svn-id: http://moon:8086/svn/software/trunk/projects/GnuRadio@380 b431acfa-c32f-4a4a-93f1-934dc6c82436

gr-jay/lib/garage_impl.cc

@@ -52,6 +52,8 @@ garage_impl::garage_impl(int sampleRate, int samplesPerSym, float kLoopFilter, f
 , m_kThreshold(kThreshold)
 , m_vmin(0)
 , m_vmax(0)
+, m_v_sig(0)
+, m_v_sig_m(0.5f)
 , m_v_thr(0)
 , m_lag_accu(0)
 , m_bit(0)
@@ -122,6 +124,9 @@ int garage_impl::general_work (int noutput_items, gr_vector_int &ninput_items, g
 	float k_leak = 0;
 	float err = 0;
 	
+	float alpha_sig = 0.5f/m_samplesPerSym;
+	float alpha_sig_m = alpha_sig/5;
+	
 	int i_i = 0;
 	while ((i_i+1) < ninput_items[0])
 	{
@@ -142,32 +147,40 @@ int garage_impl::general_work (int noutput_items, gr_vector_int &ninput_items, g
 		m_vmin = m_vmin + rho*(m_v_thr - m_vmin);
 		m_vmax = m_vmax + rho*(m_v_thr - m_vmax);
 
-		bool isSignal = (m_v_thr >= loopThreshold);
+		// Signal detection
+		float y_nodc = (y-m_v_thr);
+		m_v_sig = (1.f-alpha_sig)*m_v_sig + alpha_sig*y_nodc*y_nodc;
+		m_v_sig_m = (1.f-alpha_sig_m)*m_v_sig_m + alpha_sig_m*y;
+		bool isSignal = m_v_sig >= loopThreshold;
 
-		// Detect bit change
 		int bitChg = 0;
-		if (m_bit == 1)
+		if (isSignal)
 		{
-			if (y < (hyst_thr*m_v_thr))
+		
+			// Detect bit change
+			if (m_bit == 1)
 			{
-				m_bit = 0;
-				bitChg = 1;
+				if (y < (hyst_thr*m_v_thr))
+				{
+					m_bit = 0;
+					bitChg = 1;
+				}
 			}
-		}
-		else 
-		{
-			if (y > (hyst_thr*m_v_thr))
+			else 
 			{
-				m_bit = 1;
-				bitChg = 1;
+				if (y > (hyst_thr*m_v_thr))
+				{
+					m_bit = 1;
+					bitChg = 1;
+				}
 			}
 		}
 
-		bitProcessGap(bitChg && isSignal);
+		bitProcessGap(bitChg);
 
 		// Calc error
 		err = 0;
-		if (bitChg && isSignal)
+		if (bitChg)
 		{
 			err = -(m_count - (int)(m_samplesPerSym/2));
 		}
@@ -185,10 +198,13 @@ int garage_impl::general_work (int noutput_items, gr_vector_int &ninput_items, g
 		{
 			out[outCount++] = (float)m_bit;
 			m_count = countReload;
-			bitRecord(m_bit);
-			if (m_pFile_bits)
+			if (isSignal)
 			{
-				fprintf(m_pFile_bits, "%f %f\n", (float)m_sampleCounter/m_sampleRate, y);
+				bitRecord(m_bit);
+				if (m_pFile_bits)
+				{
+					fprintf(m_pFile_bits, "%f %f\n", (float)m_sampleCounter/m_sampleRate, y);
+				}
 			}
 		}
 		else

gr-jay/lib/garage_impl.h

@@ -39,6 +39,8 @@ class garage_impl : public garage
         float m_kThreshold;
         float m_vmin;
         float m_vmax;
+        float m_v_sig;
+        float m_v_sig_m;
         float m_v_thr;
         float m_lag_accu;
         int m_bit;