add support for software IQ imbalance correction

this functionality depend on the gr-iqbal blocks developed by Sylvain
Munaut and is a compile time dependency:

http://cgit.osmocom.org/cgit/gr-iqbal

CMakeLists.txt

@@ -109,6 +109,7 @@ set(GRC_BLOCKS_DIR      ${GR_PKG_DATA_DIR}/grc/blocks)
 ########################################################################
 find_package(Gruel)
 find_package(GnuradioCore)
+find_package(GnuradioIQBalance)
 find_package(UHD)
 find_package(GnuradioUHD)
 find_package(GnuradioFCD)

cmake/Modules/FindGnuradioIQBalance.cmake

@@ -0,0 +1,29 @@
+INCLUDE(FindPkgConfig)
+PKG_CHECK_MODULES(PC_GNURADIO_IQBALANCE gnuradio-iqbalance)
+
+FIND_PATH(
+    GNURADIO_IQBALANCE_INCLUDE_DIRS
+    NAMES iqbalance_api.h
+    HINTS $ENV{GNURADIO_IQBALANCE_DIR}/include/iqbalance
+        ${PC_GNURADIO_IQBALANCE_INCLUDEDIR}
+        ${CMAKE_INSTALL_PREFIX}/include/iqbalance
+    PATHS /usr/local/include/iqbalance
+          /usr/include/iqbalance
+)
+
+FIND_LIBRARY(
+    GNURADIO_IQBALANCE_LIBRARIES
+    NAMES gnuradio-iqbalance
+    HINTS $ENV{GNURADIO_IQBALANCE_DIR}/lib
+        ${PC_GNURADIO_IQBALANCE_LIBDIR}
+        ${CMAKE_INSTALL_PREFIX}/lib64
+        ${CMAKE_INSTALL_PREFIX}/lib
+    PATHS /usr/local/lib
+          /usr/local/lib64
+          /usr/lib
+          /usr/lib64
+)
+
+INCLUDE(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(GNURADIO_IQBALANCE DEFAULT_MSG GNURADIO_IQBALANCE_LIBRARIES GNURADIO_IQBALANCE_INCLUDE_DIRS)
+MARK_AS_ADVANCED(GNURADIO_IQBALANCE_LIBRARIES GNURADIO_IQBALANCE_INCLUDE_DIRS)

grc/gen_osmosdr_blocks.py

@@ -32,6 +32,7 @@ self.\$(id).set_sample_rate(\$sample_rate)
 \#if \$nchan() > $n
 self.\$(id).set_center_freq(\$freq$(n), $n)
 self.\$(id).set_freq_corr(\$corr$(n), $n)
+self.\$(id).set_iq_balance_mode(\$iq_balance_mode$(n), $n)
 self.\$(id).set_gain_mode(\$gain_mode$(n), $n)
 self.\$(id).set_gain(\$gain$(n), $n)
 self.\$(id).set_if_gain(\$if_gain$(n), $n)
@@ -45,6 +46,7 @@ self.\$(id).set_antenna(\$ant$(n), $n)
 	#for $n in range($max_nchan)
 	<callback>set_center_freq(\$freq$(n), $n)</callback>
 	<callback>set_freq_corr(\$corr$(n), $n)</callback>
+	<callback>set_iq_balance_mode(\$iq_balance_mode$(n), $n)</callback>
 	<callback>set_gain_mode(\$gain_mode$(n), $n)</callback>
 	<callback>set_gain(\$gain$(n), $n)</callback>
 	<callback>set_if_gain(\$if_gain$(n), $n)</callback>
@@ -149,6 +151,14 @@ The center frequency is the frequency the RF chain is tuned to.
 Freq. Corr.:
 The frequency correction factor in parts per million (ppm). Set to 0 if unknown.
 
+IQ Balance Mode:
+Controls the behavior of software IQ imbalance corrrection.
+  Off: Disable correction algorithm (pass through)
+  Manual: Keep last estimated correction when switched from Automatic to Manual
+  Automatic: Find the best solution to compensate for image signals.
+
+This functionality depends on http://cgit.osmocom.org/cgit/gr-iqbal/
+
 Gain Mode:
 Chooses between the manual (default) and automatic gain mode where appropriate.
 Currently, only rtlsdr devices support automatic gain mode.
@@ -187,6 +197,25 @@ PARAMS_TMPL = """
 		<type>real</type>
 		<hide>\#if \$nchan() > $n then 'none' else 'all'#</hide>
 	</param>
+	<param>
+		<name>Ch$(n): IQ Balance Mode</name>
+		<key>iq_balance_mode$(n)</key>
+		<value>0</value>
+		<type>int</type>
+		<hide>\#if \$nchan() > $n then 'none' else 'all'#</hide>
+		<option>
+			<name>Off</name>
+			<key>0</key>
+		</option>
+		<option>
+			<name>Manual</name>
+			<key>1</key>
+		</option>
+		<option>
+			<name>Automatic</name>
+			<key>2</key>
+		</option>
+	</param>
 	<param>
 		<name>Ch$(n): Gain Mode</name>
 		<key>gain_mode$(n)</key>
@@ -198,7 +227,7 @@ PARAMS_TMPL = """
 			<key>0</key>
 		</option>
 		<option>
-			<name>Auto</name>
+			<name>Automatic</name>
 			<key>1</key>
 		</option>
 	</param>

include/osmosdr/osmosdr_source_c.h

@@ -229,6 +229,30 @@ public:
    * \return antenna the actual antenna's name
    */
   virtual std::string get_antenna( size_t chan = 0 ) = 0;
+
+  enum IQBalanceMode {
+    IQBalanceOff = 0,
+    IQBalanceManual,
+    IQBalanceAutomatic
+  };
+
+  /*!
+   * Set the RX frontend IQ balance mode.
+   *
+   * \param mode iq balance correction mode: 0 = Off, 1 = Manual, 2 = Automatic
+   * \param chan the channel index 0 to N-1
+   */
+  virtual void set_iq_balance_mode( int mode, size_t chan = 0 ) = 0;
+
+  /*!
+   * Set the RX frontend IQ balance correction.
+   * Use this to adjust the magnitude and phase of I and Q.
+   *
+   * \param correction the complex correction value
+   * \param chan the channel index 0 to N-1
+   */
+  virtual void set_iq_balance( const std::complex<double> &correction,
+                               size_t chan = 0 ) = 0;
 };
 
 #endif /* INCLUDED_OSMOSDR_SOURCE_C_H */

lib/CMakeLists.txt

@@ -47,6 +47,13 @@ GR_OSMOSDR_APPEND_LIBS(
     ${GNURADIO_CORE_LIBRARIES}
 )
 
+if(GNURADIO_IQBALANCE_FOUND)
+    message(STATUS "Will build with gnuradio iqbalance support.")
+    add_definitions(-DHAVE_IQBALANCE=1)
+    include_directories(APPEND ${GNURADIO_IQBALANCE_INCLUDE_DIRS})
+    GR_OSMOSDR_APPEND_LIBS(${GNURADIO_IQBALANCE_LIBRARIES})
+endif()
+
 ########################################################################
 # Setup OsmoSDR component
 ########################################################################

lib/osmosdr_source_c_impl.cc

@@ -173,70 +173,81 @@ osmosdr_source_c_impl::osmosdr_source_c_impl (const std::string &args)
 //    BOOST_FOREACH( dict_t::value_type &entry, dict )
 //      std::cerr << "'" << entry.first << "' = '" << entry.second << "'" << std::endl;
 
+    osmosdr_src_iface *iface = NULL;
+    gr_basic_block_sptr block;
+
 #ifdef ENABLE_OSMOSDR
     if ( dict.count("osmosdr") ) {
       osmosdr_src_c_sptr src = osmosdr_make_src_c( arg );
-
+      block = src; iface = src.get();
-      for (size_t i = 0; i < src->get_num_channels(); i++)
-        connect(src, i, self(), channel++);
-
-      _devs.push_back( src.get() );
     }
 #endif
 
 #ifdef ENABLE_FCD
     if ( dict.count("fcd") ) {
       fcd_source_sptr src = make_fcd_source( arg );
-      connect(src, 0, self(), channel++);
+      block = src; iface = src.get();
-      _devs.push_back( src.get() );
     }
 #endif
 
 #ifdef ENABLE_FILE
     if ( dict.count("file") ) {
       file_source_c_sptr src = make_file_source_c( arg );
-      connect(src, 0, self(), channel++);
+      block = src; iface = src.get();
-      _devs.push_back( src.get() );
     }
 #endif
 
 #ifdef ENABLE_RTL
     if ( dict.count("rtl") ) {
       rtl_source_c_sptr src = make_rtl_source_c( arg );
-      connect(src, 0, self(), channel++);
+      block = src; iface = src.get();
-      _devs.push_back( src.get() );
     }
 #endif
 
 #ifdef ENABLE_RTL_TCP
     if ( dict.count("rtl_tcp") ) {
       rtl_tcp_source_c_sptr src = make_rtl_tcp_source_c( arg );
-      connect(src, 0, self(), channel++);
+      block = src; iface = src.get();
-      _devs.push_back( src.get() );
     }
 #endif
 
 #ifdef ENABLE_UHD
     if ( dict.count("uhd") ) {
       uhd_source_c_sptr src = make_uhd_source_c( arg );
-
+      block = src; iface = src.get();
-      for (size_t i = 0; i < src->get_num_channels(); i++)
-        connect(src, i, self(), channel++);
-
-      _devs.push_back( src.get() );
     }
 #endif
 
 #ifdef ENABLE_MIRI
     if ( dict.count("miri") ) {
       miri_source_c_sptr src = make_miri_source_c( arg );
-
+      block = src; iface = src.get();
-      for (size_t i = 0; i < src->get_num_channels(); i++)
-        connect(src, i, self(), channel++);
-
-      _devs.push_back( src.get() );
     }
 #endif
+
+    if ( iface != NULL && long(block.get()) != 0 ) {
+      _devs.push_back( iface );
+
+      for (size_t i = 0; i < iface->get_num_channels(); i++) {
+#ifdef HAVE_IQBALANCE
+        iqbalance_optimize_c_sptr iq_opt = iqbalance_make_optimize_c( 0 );
+        iqbalance_fix_cc_sptr iq_fix = iqbalance_make_fix_cc();
+
+        connect(block, i, iq_fix, 0);
+        connect(iq_fix, 0, self(), channel++);
+
+        connect(block, i, iq_opt, 0);
+        msg_connect(iq_opt, "iqbal_corr", iq_fix, "iqbal_corr");
+
+        _iq_opt.push_back( iq_opt.get() );
+        _iq_fix.push_back( iq_fix.get() );
+#else
+        connect(block, i, self(), channel++);
+#endif
+      }
+    } else if ( (iface != NULL) || (long(block.get()) != 0) )
+      throw std::runtime_error("Eitner iface or block are NULL.");
+
   }
 
   if (!_devs.size())
@@ -305,6 +316,24 @@ double osmosdr_source_c_impl::set_sample_rate(double rate)
     BOOST_FOREACH( osmosdr_src_iface *dev, _devs )
       sample_rate = dev->set_sample_rate(rate);
 
+#ifdef HAVE_IQBALANCE
+    size_t channel = 0;
+    BOOST_FOREACH( osmosdr_src_iface *dev, _devs ) {
+      for (size_t dev_chan = 0; dev_chan < dev->get_num_channels(); dev_chan++) {
+        if ( channel < _iq_opt.size() ) {
+          iqbalance_optimize_c *opt = _iq_opt[channel];
+
+          if ( opt->period() > 0 ) { /* optimize is enabled */
+            opt->set_period( dev->get_sample_rate() / 5 );
+            opt->reset();
+          }
+        }
+
+        channel++;
+      }
+    }
+#endif
+
     _sample_rate = sample_rate;
   }
 
@@ -542,3 +571,61 @@ std::string osmosdr_source_c_impl::get_antenna( size_t chan )
 
   return "";
 }
+
+void osmosdr_source_c_impl::set_iq_balance_mode( int mode, size_t chan )
+{
+#ifdef HAVE_IQBALANCE
+  size_t channel = 0;
+  BOOST_FOREACH( osmosdr_src_iface *dev, _devs ) {
+    for (size_t dev_chan = 0; dev_chan < dev->get_num_channels(); dev_chan++) {
+      if ( chan == channel++ ) {
+        if ( chan < _iq_opt.size() && chan < _iq_fix.size() ) {
+          iqbalance_optimize_c *opt = _iq_opt[chan];
+          iqbalance_fix_cc *fix = _iq_fix[chan];
+
+          if ( IQBalanceOff == mode  ) {
+            opt->set_period( 0 );
+            /* store current values in order to be able to restore them later */
+            _vals[ chan ] = std::pair< float, float >( fix->mag(), fix->phase() );
+            fix->set_mag( 0.0f );
+            fix->set_phase( 0.0f );
+          } else if ( IQBalanceManual == mode ) {
+            if ( opt->period() == 0 ) { /* transition from Off to Manual */
+              /* restore previous values */
+              std::pair< float, float > val = _vals[ chan ];
+              fix->set_mag( val.first );
+              fix->set_phase( val.second );
+            }
+            opt->set_period( 0 );
+          } else if ( IQBalanceAutomatic == mode ) {
+            opt->set_period( dev->get_sample_rate() / 5 );
+            opt->reset();
+          }
+        }
+      }
+    }
+  }
+#endif
+}
+
+void osmosdr_source_c_impl::set_iq_balance( const std::complex<double> &correction, size_t chan )
+{
+#ifdef HAVE_IQBALANCE
+  size_t channel = 0;
+  BOOST_FOREACH( osmosdr_src_iface *dev, _devs ) {
+    for (size_t dev_chan = 0; dev_chan < dev->get_num_channels(); dev_chan++) {
+      if ( chan == channel++ ) {
+        if ( chan < _iq_opt.size() && chan < _iq_fix.size() ) {
+          iqbalance_optimize_c *opt = _iq_opt[chan];
+          iqbalance_fix_cc *fix = _iq_fix[chan];
+
+          if ( opt->period() == 0 ) { /* automatic optimization desabled */
+            fix->set_mag( correction.real() );
+            fix->set_phase( correction.imag() );
+          }
+        }
+      }
+    }
+  }
+#endif
+}

lib/osmosdr_source_c_impl.h

@@ -22,6 +22,11 @@
 
 #include <osmosdr_source_c.h>
 
+#ifdef HAVE_IQBALANCE
+#include <iqbalance_optimize_c.h>
+#include <iqbalance_fix_cc.h>
+#endif
+
 #include <osmosdr_src_iface.h>
 
 #include <map>
@@ -57,6 +62,9 @@ public:
   std::string set_antenna( const std::string & antenna, size_t chan = 0 );
   std::string get_antenna( size_t chan = 0 );
 
+  void set_iq_balance_mode( int mode, size_t chan = 0 );
+  void set_iq_balance( const std::complex<double> &correction, size_t chan = 0 );
+
 private:
   osmosdr_source_c_impl (const std::string & args);  	// private constructor
 
@@ -72,6 +80,11 @@ private:
   std::map< size_t, double > _if_gain;
   std::map< size_t, std::string > _antenna;
   std::vector< osmosdr_src_iface * > _devs;
+#ifdef HAVE_IQBALANCE
+  std::vector< iqbalance_fix_cc * > _iq_fix;
+  std::vector< iqbalance_optimize_c * > _iq_opt;
+  std::map< size_t, std::pair<float, float> > _vals;
+#endif
 };
 
 #endif /* INCLUDED_OSMOSDR_SOURCE_C_IMPL_H */