- improved signal detection and thresholding

- no lag accu update if no signal
- don't print packets

git-svn-id: http://moon:8086/svn/software/trunk/projects/GnuRadio@389 b431acfa-c32f-4a4a-93f1-934dc6c82436

gr-jay/lib/garage_impl.cc

@@ -25,6 +25,7 @@
 #include <gnuradio/io_signature.h>
 #include "garage_impl.h"
 	
+#define WITH_PRINT_PACKETS		0
 #define WITH_DEBUG_MESSAGES		0
 #define WITH_DEBUG_FILE			0
 	
@@ -47,6 +48,7 @@ garage_impl::garage_impl(int sampleRate, int samplesPerSym, float kLoopFilter, f
 , m_sampleRate(sampleRate)
 , m_samplesPerSym(samplesPerSym)
 , m_count(samplesPerSym)
+, m_isSignal(false)
 , m_baudRate((float)m_sampleRate/m_samplesPerSym)
 , m_kLoopFilter(kLoopFilter)
 , m_kThreshold(kThreshold)
@@ -122,7 +124,7 @@ int garage_impl::general_work (int noutput_items, gr_vector_int &ninput_items, g
 	float loopThreshold = m_kThreshold;
 	float k_lead = 1.0e-1f;
 	float k_lag = 1.0e-4f;
-	float k_leak = 0;
+	float rho_leak = 0.9999;
 	float err = 0;
 	
 	float alpha_sig = 0.5f/m_samplesPerSym;
@@ -150,8 +152,23 @@ int garage_impl::general_work (int noutput_items, gr_vector_int &ninput_items, g
 		m_dc_corr += alpha_thr*(m_vmax + m_vmin);
 		
 		// Signal detection
-		m_v_sig = (1.f-alpha_sig)*m_v_sig + alpha_sig*y*y;
+		float yd = std::abs(y)-m_vmax;
-		bool isSignal = m_v_sig >= loopThreshold;
+		m_v_sig = (1.f-alpha_sig)*m_v_sig + alpha_sig*yd*yd;
+		
+		if (!m_isSignal)
+		{
+			if (m_v_sig <= loopThreshold)
+			{
+				m_isSignal = true;
+			}
+		}
+		else
+		{
+			if (m_v_sig > 1.2*loopThreshold)
+			{
+				m_isSignal = false;
+			}
+		}
 
 		// Integrate and dump
 		float k_id = 1.f/((1+m_lag_accu)*m_samplesPerSym);
@@ -161,20 +178,26 @@ int garage_impl::general_work (int noutput_items, gr_vector_int &ninput_items, g
 			float accu = m_id_accu;
 			m_id_accu = 0;
 			int bit_id = (int)(accu >= 0.0);
-			out[outCount++] = (float)bit_id;
+			if (m_isSignal)
-			if (isSignal)
 			{
+#if WITH_PRINT_PACKETS
 				bitRecord(bit_id);
-				if (m_pFile_bits)
+#endif
-				{
+				out[outCount++] = (float)bit_id;
-					fprintf(m_pFile_bits, "%f %f\n", (float)m_sampleCounter/m_sampleRate, accu);
+			}
-				}
+			else
+			{
+				out[outCount++] = (float)0xFFFFFFFF;
+			}
+			if (m_pFile_bits)
+			{
+				fprintf(m_pFile_bits, "%f %f\n", (float)m_sampleCounter/m_sampleRate, accu);
 			}
 		}
 
 		// Zero crossing detector
 		int bitChg = 0;
-		if (isSignal)
+		if (m_isSignal)
 		{
 			if (m_bitZeroCross == 1)
 			{
@@ -194,8 +217,9 @@ int garage_impl::general_work (int noutput_items, gr_vector_int &ninput_items, g
 			}
 		}
 
+#if WITH_PRINT_PACKETS
 		bitProcessGap(bitChg);
-
+#endif
 		// Calc error
 		err = 0;
 		if (bitChg)
@@ -205,9 +229,19 @@ int garage_impl::general_work (int noutput_items, gr_vector_int &ninput_items, g
 
 		float vcorr = k_leadLag*k_lead*err + m_lag_accu;
 
-		// Lag part of loop filter
+		m_lag_accu *= rho_leak;
-		m_lag_accu += k_leadLag*k_lag*err;
+		if (m_isSignal)
-		m_lag_accu *= (1.f - k_leak);
+		{
+			if  (m_lag_accu > -0.5f and m_lag_accu < 0.5f)
+			{
+				// Lag part of loop filter
+				m_lag_accu += k_leadLag*k_lag*err;
+			}
+		}			
+		else
+		{
+			m_lag_accu = 0;
+		}
 
 		m_baudRate = (float)m_sampleRate/((1+m_lag_accu)*m_samplesPerSym);
 
@@ -230,6 +264,11 @@ int garage_impl::general_work (int noutput_items, gr_vector_int &ninput_items, g
 		m_i += (1+vcorr);
 		i_i = (int)m_i;
 		
+		if (outCount >= noutput_items)
+		{
+			break;
+		}
+
 		inCount++;
 		if (inCount >= ninput_items[0])
 		{

gr-jay/lib/garage_impl.h

@@ -34,6 +34,7 @@ class garage_impl : public garage
 	int m_sampleRate;
 	int m_samplesPerSym;
         int m_count;
+        bool m_isSignal;
 	float m_baudRate;
         float m_kLoopFilter;
         float m_kThreshold;