Added new blocks for clock freqeuncy correction
diff --git a/lib/misc_utils/controlled_const_source_f_impl.cc b/lib/misc_utils/controlled_const_source_f_impl.cc
new file mode 100644
index 0000000..d58f04f
--- /dev/null
+++ b/lib/misc_utils/controlled_const_source_f_impl.cc
@@ -0,0 +1,86 @@
+/* -*- c++ -*- */
+/* 
+ * Copyright 2014 <+YOU OR YOUR COMPANY+>.
+ * 
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gnuradio/io_signature.h>
+#include "controlled_const_source_f_impl.h"
+
+namespace gr {
+  namespace gsm {
+
+    controlled_const_source_f::sptr
+    controlled_const_source_f::make(float constant)
+    {
+      return gnuradio::get_initial_sptr
+        (new controlled_const_source_f_impl(constant));
+    }
+    
+    void controlled_const_source_f_impl::set_constant_msg(pmt::pmt_t msg){
+      if(pmt::is_real(msg)){
+          set_constant(pmt::to_double(msg));
+      }
+    }
+
+    /*
+     * The private constructor
+     */
+    controlled_const_source_f_impl::controlled_const_source_f_impl(float constant)
+      : gr::sync_block("controlled_const_source_f",
+              gr::io_signature::make(0, 0, 0),
+              gr::io_signature::make(1, 1, sizeof(float)))
+    {
+        set_constant(constant);
+        message_port_register_in(pmt::mp("constant_msg"));
+        set_msg_handler(pmt::mp("constant_msg"), boost::bind(&controlled_const_source_f_impl::set_constant_msg, this, _1));
+    }
+
+    /*
+     * Our virtual destructor.
+     */
+    controlled_const_source_f_impl::~controlled_const_source_f_impl()
+    {
+    }
+
+    int
+    controlled_const_source_f_impl::work(int noutput_items,
+			  gr_vector_const_void_star &input_items,
+			  gr_vector_void_star &output_items)
+    {
+      float *optr = (float*)output_items[0];
+      float t;
+      
+      t = d_constant;
+      std::fill_n(optr, noutput_items, t);
+
+      return noutput_items;
+    }
+    
+    void controlled_const_source_f_impl::set_constant(float constant){
+      d_constant = constant;
+    }
+    
+
+
+  } /* namespace gsm */
+} /* namespace gr */
+