Implemented crude timing recovery using zero crossings but no resampling

4 files changed, 281 insertions, 299 deletions

diff --git a/gr-noaa/grc/usrp_rx_hrpt.grc b/gr-noaa/grc/usrp_rx_hrpt.grc
index d3c6603ad..b304bd359 100644
--- a/gr-noaa/grc/usrp_rx_hrpt.grc
+++ b/gr-noaa/grc/usrp_rx_hrpt.grc
@@ -1,6 +1,6 @@
 <?xml version='1.0' encoding='ASCII'?>
 <flow_graph>
-  <timestamp>Sat Aug 29 11:48:56 2009</timestamp>
+  <timestamp>Sat Aug 29 13:16:19 2009</timestamp>
   <block>
     <key>options</key>
     <param>
@@ -257,85 +257,56 @@
     </param>
   </block>
   <block>
-    <key>wxgui_fftsink2</key>
+    <key>variable</key>
     <param>
       <key>id</key>
-      <value>rx_fftsink</value>
+      <value>max_carrier_offset</value>
     </param>
     <param>
       <key>_enabled</key>
       <value>True</value>
     </param>
     <param>
-      <key>type</key>
-      <value>complex</value>
-    </param>
-    <param>
-      <key>title</key>
-      <value>RX Spectrum</value>
-    </param>
-    <param>
-      <key>samp_rate</key>
-      <value>sample_rate</value>
-    </param>
-    <param>
-      <key>baseband_freq</key>
-      <value>1698e6</value>
-    </param>
-    <param>
-      <key>y_per_div</key>
-      <value>5</value>
-    </param>
-    <param>
-      <key>y_divs</key>
-      <value>8</value>
-    </param>
-    <param>
-      <key>ref_level</key>
-      <value>20</value>
+      <key>value</key>
+      <value>2*math.pi*100e3/sample_rate</value>
     </param>
     <param>
-      <key>fft_size</key>
-      <value>1024</value>
+      <key>_coordinate</key>
+      <value>(668, 107)</value>
     </param>
     <param>
-      <key>fft_rate</key>
-      <value>30</value>
+      <key>_rotation</key>
+      <value>0</value>
     </param>
+  </block>
+  <block>
+    <key>variable</key>
     <param>
-      <key>peak_hold</key>
-      <value>False</value>
+      <key>id</key>
+      <value>max_sync_offset</value>
     </param>
     <param>
-      <key>average</key>
+      <key>_enabled</key>
       <value>True</value>
     </param>
     <param>
-      <key>avg_alpha</key>
-      <value>0.1</value>
-    </param>
-    <param>
-      <key>grid_pos</key>
-      <value>0, 0, 1, 1</value>
-    </param>
-    <param>
-      <key>notebook</key>
-      <value>displays, 0</value>
+      <key>value</key>
+      <value>0.01</value>
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(194, 263)</value>
+      <value>(665, 173)</value>
     </param>
     <param>
       <key>_rotation</key>
-      <value>180</value>
+      <value>0</value>
     </param>
   </block>
   <block>
     <key>wxgui_scopesink2</key>
     <param>
       <key>id</key>
-      <value>wxgui_scopesink2_0</value>
+      <value>wxgui_scopesink2_0_0</value>
     </param>
     <param>
       <key>_enabled</key>
@@ -347,7 +318,7 @@
     </param>
     <param>
       <key>title</key>
-      <value>RX Waveform</value>
+      <value>Post-PLL</value>
     </param>
     <param>
       <key>samp_rate</key>
@@ -355,7 +326,7 @@
     </param>
     <param>
       <key>v_scale</key>
-      <value>0</value>
+      <value>0.5</value>
     </param>
     <param>
       <key>t_scale</key>
@@ -375,15 +346,15 @@
     </param>
     <param>
       <key>grid_pos</key>
-      <value>1, 0, 1, 1</value>
+      <value>0, 0, 1, 1</value>
     </param>
     <param>
       <key>notebook</key>
-      <value>displays, 0</value>
+      <value>displays, 1</value>
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(198, 609)</value>
+      <value>(618, 335)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -391,38 +362,34 @@
     </param>
   </block>
   <block>
-    <key>gr_agc_xx</key>
+    <key>notebook</key>
     <param>
       <key>id</key>
-      <value>agr</value>
+      <value>displays</value>
     </param>
     <param>
       <key>_enabled</key>
       <value>True</value>
     </param>
     <param>
-      <key>type</key>
-      <value>complex</value>
-    </param>
-    <param>
-      <key>rate</key>
-      <value>1e-6</value>
+      <key>style</key>
+      <value>wx.NB_TOP</value>
     </param>
     <param>
-      <key>reference</key>
-      <value>1.0</value>
+      <key>labels</key>
+      <value>['RX','PLL','SYNC']</value>
     </param>
     <param>
-      <key>gain</key>
-      <value>1.0</value>
+      <key>grid_pos</key>
+      <value>1, 0, 1, 2</value>
     </param>
     <param>
-      <key>max_gain</key>
-      <value>1.0</value>
+      <key>notebook</key>
+      <value></value>
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(261, 494)</value>
+      <value>(9, 99)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -430,10 +397,10 @@
     </param>
   </block>
   <block>
-    <key>gr_moving_average_xx</key>
+    <key>wxgui_scopesink2</key>
     <param>
       <key>id</key>
-      <value>gr_moving_average_xx_0</value>
+      <value>wxgui_scopesink2_0_0_0</value>
     </param>
     <param>
       <key>_enabled</key>
@@ -444,66 +411,79 @@
       <value>complex</value>
     </param>
     <param>
-      <key>length</key>
-      <value>hs</value>
+      <key>title</key>
+      <value>Post-PLL</value>
     </param>
     <param>
-      <key>scale</key>
-      <value>1.0/hs</value>
+      <key>samp_rate</key>
+      <value>sample_rate</value>
     </param>
     <param>
-      <key>max_iter</key>
-      <value>4000</value>
+      <key>v_scale</key>
+      <value>0.5</value>
     </param>
     <param>
-      <key>_coordinate</key>
-      <value>(434, 502)</value>
+      <key>t_scale</key>
+      <value>20.0/sample_rate</value>
     </param>
     <param>
-      <key>_rotation</key>
-      <value>0</value>
+      <key>ac_couple</key>
+      <value>False</value>
     </param>
-  </block>
-  <block>
-    <key>variable</key>
     <param>
-      <key>id</key>
-      <value>max_carrier_offset</value>
+      <key>xy_mode</key>
+      <value>True</value>
     </param>
     <param>
-      <key>_enabled</key>
-      <value>True</value>
+      <key>num_inputs</key>
+      <value>1</value>
     </param>
     <param>
-      <key>value</key>
-      <value>2*math.pi*100e3/sample_rate</value>
+      <key>grid_pos</key>
+      <value>1, 0, 1, 1</value>
+    </param>
+    <param>
+      <key>notebook</key>
+      <value>displays, 1</value>
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(668, 107)</value>
+      <value>(618, 614)</value>
     </param>
     <param>
       <key>_rotation</key>
-      <value>0</value>
+      <value>180</value>
     </param>
   </block>
   <block>
-    <key>variable</key>
+    <key>noaa_hrpt_sync_cc</key>
     <param>
       <key>id</key>
-      <value>max_sync_offset</value>
+      <value>sync</value>
     </param>
     <param>
       <key>_enabled</key>
       <value>True</value>
     </param>
     <param>
-      <key>value</key>
-      <value>0.01</value>
+      <key>alpha</key>
+      <value>sync_alpha</value>
+    </param>
+    <param>
+      <key>beta</key>
+      <value>sync_alpha**2/4.0</value>
+    </param>
+    <param>
+      <key>sps</key>
+      <value>sps</value>
+    </param>
+    <param>
+      <key>max_offset</key>
+      <value>max_sync_offset</value>
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(665, 173)</value>
+      <value>(865, 494)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -511,140 +491,156 @@
     </param>
   </block>
   <block>
-    <key>variable_slider</key>
+    <key>wxgui_scopesink2</key>
     <param>
       <key>id</key>
-      <value>pll_alpha</value>
+      <value>wxgui_scopesink2_0_0_0_0</value>
     </param>
     <param>
       <key>_enabled</key>
       <value>True</value>
     </param>
     <param>
-      <key>label</key>
-      <value>PLL Alpha</value>
+      <key>type</key>
+      <value>complex</value>
     </param>
     <param>
-      <key>value</key>
-      <value>0.005</value>
+      <key>title</key>
+      <value>Post-SYNC</value>
     </param>
     <param>
-      <key>min</key>
-      <value>0.0</value>
+      <key>samp_rate</key>
+      <value>sym_rate</value>
     </param>
     <param>
-      <key>max</key>
+      <key>v_scale</key>
       <value>0.5</value>
     </param>
     <param>
-      <key>num_steps</key>
-      <value>500</value>
+      <key>t_scale</key>
+      <value>20.0/sym_rate</value>
     </param>
     <param>
-      <key>style</key>
-      <value>wx.SL_HORIZONTAL</value>
+      <key>ac_couple</key>
+      <value>False</value>
     </param>
     <param>
-      <key>converver</key>
-      <value>float_converter</value>
+      <key>xy_mode</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>1</value>
     </param>
     <param>
       <key>grid_pos</key>
-      <value>0, 0, 1, 1</value>
+      <value>1, 0, 1, 1</value>
     </param>
     <param>
       <key>notebook</key>
-      <value></value>
+      <value>displays, 2</value>
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(192, 100)</value>
+      <value>(872, 607)</value>
     </param>
     <param>
       <key>_rotation</key>
-      <value>0</value>
+      <value>180</value>
     </param>
   </block>
   <block>
-    <key>variable_slider</key>
+    <key>wxgui_scopesink2</key>
     <param>
       <key>id</key>
-      <value>sync_alpha</value>
+      <value>wxgui_scopesink2_0_0_1</value>
     </param>
     <param>
       <key>_enabled</key>
       <value>True</value>
     </param>
     <param>
-      <key>label</key>
-      <value>SYNC Alpha</value>
+      <key>type</key>
+      <value>complex</value>
     </param>
     <param>
-      <key>value</key>
-      <value>0.005</value>
+      <key>title</key>
+      <value>Post-SYNC</value>
     </param>
     <param>
-      <key>min</key>
-      <value>0.0</value>
+      <key>samp_rate</key>
+      <value>sym_rate</value>
     </param>
     <param>
-      <key>max</key>
+      <key>v_scale</key>
       <value>0.5</value>
     </param>
     <param>
-      <key>num_steps</key>
-      <value>500</value>
+      <key>t_scale</key>
+      <value>20.0/sym_rate</value>
     </param>
     <param>
-      <key>style</key>
-      <value>wx.SL_HORIZONTAL</value>
+      <key>ac_couple</key>
+      <value>False</value>
     </param>
     <param>
-      <key>converver</key>
-      <value>float_converter</value>
+      <key>xy_mode</key>
+      <value>False</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>1</value>
     </param>
     <param>
       <key>grid_pos</key>
-      <value>0, 1, 1, 1</value>
+      <value>0, 0, 1, 1</value>
     </param>
     <param>
       <key>notebook</key>
-      <value></value>
+      <value>displays, 2</value>
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(344, 101)</value>
+      <value>(872, 341)</value>
     </param>
     <param>
       <key>_rotation</key>
-      <value>0</value>
+      <value>180</value>
     </param>
   </block>
   <block>
-    <key>noaa_hrpt_pll_cc</key>
+    <key>gr_agc_xx</key>
     <param>
       <key>id</key>
-      <value>noaa_hrpt_pll_cc_0</value>
+      <value>agr</value>
     </param>
     <param>
       <key>_enabled</key>
       <value>True</value>
     </param>
     <param>
-      <key>alpha</key>
-      <value>pll_alpha</value>
+      <key>type</key>
+      <value>complex</value>
     </param>
     <param>
-      <key>beta</key>
-      <value>pll_alpha**2/4.0</value>
+      <key>rate</key>
+      <value>1e-6</value>
     </param>
     <param>
-      <key>max_offset</key>
-      <value>max_carrier_offset</value>
+      <key>reference</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>gain</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>max_gain</key>
+      <value>1.0</value>
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(628, 502)</value>
+      <value>(261, 494)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -652,69 +648,41 @@
     </param>
   </block>
   <block>
-    <key>wxgui_scopesink2</key>
+    <key>noaa_hrpt_pll_cc</key>
     <param>
       <key>id</key>
-      <value>wxgui_scopesink2_0_0</value>
+      <value>noaa_hrpt_pll_cc_0</value>
     </param>
     <param>
       <key>_enabled</key>
       <value>True</value>
     </param>
     <param>
-      <key>type</key>
-      <value>complex</value>
-    </param>
-    <param>
-      <key>title</key>
-      <value>Post-PLL</value>
-    </param>
-    <param>
-      <key>samp_rate</key>
-      <value>sample_rate</value>
-    </param>
-    <param>
-      <key>v_scale</key>
-      <value>0.5</value>
-    </param>
-    <param>
-      <key>t_scale</key>
-      <value>20.0/sample_rate</value>
-    </param>
-    <param>
-      <key>ac_couple</key>
-      <value>False</value>
-    </param>
-    <param>
-      <key>xy_mode</key>
-      <value>False</value>
-    </param>
-    <param>
-      <key>num_inputs</key>
-      <value>1</value>
+      <key>alpha</key>
+      <value>pll_alpha</value>
     </param>
     <param>
-      <key>grid_pos</key>
-      <value>0, 0, 1, 1</value>
+      <key>beta</key>
+      <value>pll_alpha**2/4.0</value>
     </param>
     <param>
-      <key>notebook</key>
-      <value>displays, 1</value>
+      <key>max_offset</key>
+      <value>max_carrier_offset</value>
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(618, 335)</value>
+      <value>(628, 502)</value>
     </param>
     <param>
       <key>_rotation</key>
-      <value>180</value>
+      <value>0</value>
     </param>
   </block>
   <block>
-    <key>wxgui_scopesink2</key>
+    <key>wxgui_fftsink2</key>
     <param>
       <key>id</key>
-      <value>wxgui_scopesink2_0_0_1</value>
+      <value>rx_fftsink</value>
     </param>
     <param>
       <key>_enabled</key>
@@ -726,78 +694,59 @@
     </param>
     <param>
       <key>title</key>
-      <value>Post-SYNC</value>
+      <value>RX Spectrum</value>
     </param>
     <param>
       <key>samp_rate</key>
       <value>sample_rate</value>
     </param>
     <param>
-      <key>v_scale</key>
-      <value>0.5</value>
-    </param>
-    <param>
-      <key>t_scale</key>
-      <value>20.0/sample_rate</value>
-    </param>
-    <param>
-      <key>ac_couple</key>
-      <value>False</value>
-    </param>
-    <param>
-      <key>xy_mode</key>
-      <value>False</value>
+      <key>baseband_freq</key>
+      <value>1698e6</value>
     </param>
     <param>
-      <key>num_inputs</key>
-      <value>1</value>
+      <key>y_per_div</key>
+      <value>5</value>
     </param>
     <param>
-      <key>grid_pos</key>
-      <value>0, 0, 1, 1</value>
+      <key>y_divs</key>
+      <value>8</value>
     </param>
     <param>
-      <key>notebook</key>
-      <value>displays, 2</value>
+      <key>ref_level</key>
+      <value>20</value>
     </param>
     <param>
-      <key>_coordinate</key>
-      <value>(872, 341)</value>
+      <key>fft_size</key>
+      <value>1024</value>
     </param>
     <param>
-      <key>_rotation</key>
-      <value>180</value>
+      <key>fft_rate</key>
+      <value>30</value>
     </param>
-  </block>
-  <block>
-    <key>notebook</key>
     <param>
-      <key>id</key>
-      <value>displays</value>
+      <key>peak_hold</key>
+      <value>False</value>
     </param>
     <param>
-      <key>_enabled</key>
+      <key>average</key>
       <value>True</value>
     </param>
     <param>
-      <key>style</key>
-      <value>wx.NB_TOP</value>
-    </param>
-    <param>
-      <key>labels</key>
-      <value>['RX','PLL','SYNC']</value>
+      <key>avg_alpha</key>
+      <value>0.1</value>
     </param>
     <param>
       <key>grid_pos</key>
-      <value>1, 0, 1, 2</value>
+      <value>0, 0, 1, 1</value>
     </param>
     <param>
       <key>notebook</key>
-      <value></value>
+      <value>displays, 0</value>
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(9, 99)</value>
+      <value>(433, 297)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -808,7 +757,7 @@
     <key>wxgui_scopesink2</key>
     <param>
       <key>id</key>
-      <value>wxgui_scopesink2_0_0_0</value>
+      <value>wxgui_scopesink2_0</value>
     </param>
     <param>
       <key>_enabled</key>
@@ -820,7 +769,7 @@
     </param>
     <param>
       <key>title</key>
-      <value>Post-PLL</value>
+      <value>RX Waveform</value>
     </param>
     <param>
       <key>samp_rate</key>
@@ -828,7 +777,7 @@
     </param>
     <param>
       <key>v_scale</key>
-      <value>0.5</value>
+      <value>0</value>
     </param>
     <param>
       <key>t_scale</key>
@@ -840,7 +789,7 @@
     </param>
     <param>
       <key>xy_mode</key>
-      <value>True</value>
+      <value>False</value>
     </param>
     <param>
       <key>num_inputs</key>
@@ -852,46 +801,66 @@
     </param>
     <param>
       <key>notebook</key>
-      <value>displays, 1</value>
+      <value>displays, 0</value>
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(618, 614)</value>
+      <value>(434, 603)</value>
     </param>
     <param>
       <key>_rotation</key>
-      <value>180</value>
+      <value>0</value>
     </param>
   </block>
   <block>
-    <key>noaa_hrpt_sync_cc</key>
+    <key>variable_slider</key>
     <param>
       <key>id</key>
-      <value>sync</value>
+      <value>pll_alpha</value>
     </param>
     <param>
       <key>_enabled</key>
       <value>True</value>
     </param>
     <param>
-      <key>alpha</key>
-      <value>sync_alpha</value>
+      <key>label</key>
+      <value>PLL Alpha</value>
     </param>
     <param>
-      <key>beta</key>
-      <value>sync_alpha**2/4.0</value>
+      <key>value</key>
+      <value>0.001</value>
     </param>
     <param>
-      <key>sps</key>
-      <value>sps</value>
+      <key>min</key>
+      <value>0.0</value>
     </param>
     <param>
-      <key>max_offset</key>
-      <value>max_sync_offset</value>
+      <key>max</key>
+      <value>0.5</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>500</value>
+    </param>
+    <param>
+      <key>style</key>
+      <value>wx.SL_HORIZONTAL</value>
+    </param>
+    <param>
+      <key>converver</key>
+      <value>float_converter</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>0, 0, 1, 1</value>
+    </param>
+    <param>
+      <key>notebook</key>
+      <value></value>
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(865, 494)</value>
+      <value>(192, 100)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -899,62 +868,58 @@
     </param>
   </block>
   <block>
-    <key>wxgui_scopesink2</key>
+    <key>variable_slider</key>
     <param>
       <key>id</key>
-      <value>wxgui_scopesink2_0_0_0_0</value>
+      <value>sync_alpha</value>
     </param>
     <param>
       <key>_enabled</key>
       <value>True</value>
     </param>
     <param>
-      <key>type</key>
-      <value>complex</value>
+      <key>label</key>
+      <value>SYNC Alpha</value>
     </param>
     <param>
-      <key>title</key>
-      <value>Post-SYNC</value>
+      <key>value</key>
+      <value>0.001</value>
     </param>
     <param>
-      <key>samp_rate</key>
-      <value>sample_rate</value>
+      <key>min</key>
+      <value>0.0</value>
     </param>
     <param>
-      <key>v_scale</key>
+      <key>max</key>
       <value>0.5</value>
     </param>
     <param>
-      <key>t_scale</key>
-      <value>20.0/sample_rate</value>
-    </param>
-    <param>
-      <key>ac_couple</key>
-      <value>False</value>
+      <key>num_steps</key>
+      <value>500</value>
     </param>
     <param>
-      <key>xy_mode</key>
-      <value>True</value>
+      <key>style</key>
+      <value>wx.SL_HORIZONTAL</value>
     </param>
     <param>
-      <key>num_inputs</key>
-      <value>1</value>
+      <key>converver</key>
+      <value>float_converter</value>
     </param>
     <param>
       <key>grid_pos</key>
-      <value>1, 0, 1, 1</value>
+      <value>0, 1, 1, 1</value>
     </param>
     <param>
       <key>notebook</key>
-      <value>displays, 2</value>
+      <value></value>
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(872, 607)</value>
+      <value>(344, 101)</value>
     </param>
     <param>
       <key>_rotation</key>
-      <value>180</value>
+      <value>0</value>
     </param>
   </block>
   <connection>
@@ -971,12 +936,6 @@
   </connection>
   <connection>
     <source_block_id>agr</source_block_id>
-    <sink_block_id>gr_moving_average_xx_0</sink_block_id>
-    <source_key>0</source_key>
-    <sink_key>0</sink_key>
-  </connection>
-  <connection>
-    <source_block_id>agr</source_block_id>
     <sink_block_id>rx_fftsink</sink_block_id>
     <source_key>0</source_key>
     <sink_key>0</sink_key>
@@ -988,12 +947,6 @@
     <sink_key>0</sink_key>
   </connection>
   <connection>
-    <source_block_id>gr_moving_average_xx_0</source_block_id>
-    <sink_block_id>noaa_hrpt_pll_cc_0</sink_block_id>
-    <source_key>0</source_key>
-    <sink_key>0</sink_key>
-  </connection>
-  <connection>
     <source_block_id>noaa_hrpt_pll_cc_0</source_block_id>
     <sink_block_id>wxgui_scopesink2_0_0</sink_block_id>
     <source_key>0</source_key>
@@ -1023,4 +976,10 @@
     <source_key>0</source_key>
     <sink_key>0</sink_key>
   </connection>
+  <connection>
+    <source_block_id>agr</source_block_id>
+    <sink_block_id>noaa_hrpt_pll_cc_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
 </flow_graph>
diff --git a/gr-noaa/grc/usrp_rx_hrpt.py b/gr-noaa/grc/usrp_rx_hrpt.py
index ed6417335..5cfaf7842 100755
--- a/gr-noaa/grc/usrp_rx_hrpt.py
+++ b/gr-noaa/grc/usrp_rx_hrpt.py
@@ -2,7 +2,7 @@
 ##################################################
 # Gnuradio Python Flow Graph
 # Title: USRP HRPT Receiver
-# Generated: Sat Aug 29 11:48:57 2009
+# Generated: Sat Aug 29 13:16:19 2009
 ##################################################
 
 from gnuradio import gr
@@ -28,8 +28,8 @@ class usrp_rx_hrpt(grc_wxgui.top_block_gui):
 		self.sym_rate = sym_rate = 600*1109
 		self.sample_rate = sample_rate = 64e6/decim
 		self.sps = sps = sample_rate/sym_rate
-		self.sync_alpha = sync_alpha = 0.005
-		self.pll_alpha = pll_alpha = 0.005
+		self.sync_alpha = sync_alpha = 0.001
+		self.pll_alpha = pll_alpha = 0.001
 		self.max_sync_offset = max_sync_offset = 0.01
 		self.max_carrier_offset = max_carrier_offset = 2*math.pi*100e3/sample_rate
 		self.hs = hs = int(sps/2.0)
@@ -97,7 +97,6 @@ class usrp_rx_hrpt(grc_wxgui.top_block_gui):
 		# Blocks
 		##################################################
 		self.agr = gr.agc_cc(1e-6, 1.0, 1.0, 1.0)
-		self.gr_moving_average_xx_0 = gr.moving_average_cc(hs, 1.0/hs, 4000)
 		self.noaa_hrpt_pll_cc_0 = noaa.hrpt_pll_cc(pll_alpha, pll_alpha**2/4.0, max_carrier_offset)
 		self.rx_fftsink = fftsink2.fft_sink_c(
 			self.displays.GetPage(0).GetWin(),
@@ -153,9 +152,9 @@ class usrp_rx_hrpt(grc_wxgui.top_block_gui):
 		self.wxgui_scopesink2_0_0_0_0 = scopesink2.scope_sink_c(
 			self.displays.GetPage(2).GetWin(),
 			title="Post-SYNC",
-			sample_rate=sample_rate,
+			sample_rate=sym_rate,
 			v_scale=0.5,
-			t_scale=20.0/sample_rate,
+			t_scale=20.0/sym_rate,
 			ac_couple=False,
 			xy_mode=True,
 			num_inputs=1,
@@ -164,9 +163,9 @@ class usrp_rx_hrpt(grc_wxgui.top_block_gui):
 		self.wxgui_scopesink2_0_0_1 = scopesink2.scope_sink_c(
 			self.displays.GetPage(2).GetWin(),
 			title="Post-SYNC",
-			sample_rate=sample_rate,
+			sample_rate=sym_rate,
 			v_scale=0.5,
-			t_scale=20.0/sample_rate,
+			t_scale=20.0/sym_rate,
 			ac_couple=False,
 			xy_mode=False,
 			num_inputs=1,
@@ -178,15 +177,14 @@ class usrp_rx_hrpt(grc_wxgui.top_block_gui):
 		##################################################
 		self.connect((self.src, 0), (self.throttle, 0))
 		self.connect((self.throttle, 0), (self.agr, 0))
-		self.connect((self.agr, 0), (self.gr_moving_average_xx_0, 0))
 		self.connect((self.agr, 0), (self.rx_fftsink, 0))
 		self.connect((self.agr, 0), (self.wxgui_scopesink2_0, 0))
-		self.connect((self.gr_moving_average_xx_0, 0), (self.noaa_hrpt_pll_cc_0, 0))
 		self.connect((self.noaa_hrpt_pll_cc_0, 0), (self.wxgui_scopesink2_0_0, 0))
 		self.connect((self.noaa_hrpt_pll_cc_0, 0), (self.wxgui_scopesink2_0_0_0, 0))
 		self.connect((self.noaa_hrpt_pll_cc_0, 0), (self.sync, 0))
 		self.connect((self.sync, 0), (self.wxgui_scopesink2_0_0_1, 0))
 		self.connect((self.sync, 0), (self.wxgui_scopesink2_0_0_0_0, 0))
+		self.connect((self.agr, 0), (self.noaa_hrpt_pll_cc_0, 0))
 
 	def set_decim(self, decim):
 		self.decim = decim
@@ -195,17 +193,17 @@ class usrp_rx_hrpt(grc_wxgui.top_block_gui):
 	def set_sym_rate(self, sym_rate):
 		self.sym_rate = sym_rate
 		self.set_sps(self.sample_rate/self.sym_rate)
+		self.wxgui_scopesink2_0_0_0_0.set_sample_rate(self.sym_rate)
+		self.wxgui_scopesink2_0_0_1.set_sample_rate(self.sym_rate)
 
 	def set_sample_rate(self, sample_rate):
 		self.sample_rate = sample_rate
 		self.set_sps(self.sample_rate/self.sym_rate)
-		self.rx_fftsink.set_sample_rate(self.sample_rate)
-		self.wxgui_scopesink2_0.set_sample_rate(self.sample_rate)
 		self.set_max_carrier_offset(2*math.pi*100e3/self.sample_rate)
 		self.wxgui_scopesink2_0_0.set_sample_rate(self.sample_rate)
-		self.wxgui_scopesink2_0_0_1.set_sample_rate(self.sample_rate)
 		self.wxgui_scopesink2_0_0_0.set_sample_rate(self.sample_rate)
-		self.wxgui_scopesink2_0_0_0_0.set_sample_rate(self.sample_rate)
+		self.rx_fftsink.set_sample_rate(self.sample_rate)
+		self.wxgui_scopesink2_0.set_sample_rate(self.sample_rate)
 
 	def set_sps(self, sps):
 		self.sps = sps
@@ -213,17 +211,17 @@ class usrp_rx_hrpt(grc_wxgui.top_block_gui):
 
 	def set_sync_alpha(self, sync_alpha):
 		self.sync_alpha = sync_alpha
-		self._sync_alpha_slider.set_value(self.sync_alpha)
-		self._sync_alpha_text_box.set_value(self.sync_alpha)
 		self.sync.set_alpha(self.sync_alpha)
 		self.sync.set_beta(self.sync_alpha**2/4.0)
+		self._sync_alpha_slider.set_value(self.sync_alpha)
+		self._sync_alpha_text_box.set_value(self.sync_alpha)
 
 	def set_pll_alpha(self, pll_alpha):
 		self.pll_alpha = pll_alpha
-		self._pll_alpha_slider.set_value(self.pll_alpha)
-		self._pll_alpha_text_box.set_value(self.pll_alpha)
 		self.noaa_hrpt_pll_cc_0.set_alpha(self.pll_alpha)
 		self.noaa_hrpt_pll_cc_0.set_beta(self.pll_alpha**2/4.0)
+		self._pll_alpha_slider.set_value(self.pll_alpha)
+		self._pll_alpha_text_box.set_value(self.pll_alpha)
 
 	def set_max_sync_offset(self, max_sync_offset):
 		self.max_sync_offset = max_sync_offset
@@ -235,7 +233,6 @@ class usrp_rx_hrpt(grc_wxgui.top_block_gui):
 
 	def set_hs(self, hs):
 		self.hs = hs
-		self.gr_moving_average_xx_0.set_length_and_scale(self.hs, 1.0/self.hs)
 
 if __name__ == '__main__':
 	parser = OptionParser(option_class=eng_option, usage="%prog: [options]")
diff --git a/gr-noaa/lib/noaa_hrpt_sync_cc.cc b/gr-noaa/lib/noaa_hrpt_sync_cc.cc
index 47858d758..46cc277bd 100644
--- a/gr-noaa/lib/noaa_hrpt_sync_cc.cc
+++ b/gr-noaa/lib/noaa_hrpt_sync_cc.cc
@@ -27,6 +27,11 @@
 #include <noaa_hrpt_sync_cc.h>
 #include <gr_io_signature.h>
 
+inline int signum(float f)
+{
+  return f >= 0.0 ? 1 : -1;
+}
+
 noaa_hrpt_sync_cc_sptr
 noaa_make_hrpt_sync_cc(float alpha, float beta, float sps, float max_offset)
 {
@@ -37,8 +42,10 @@ noaa_hrpt_sync_cc::noaa_hrpt_sync_cc(float alpha, float beta, float sps, float m
   : gr_block("noaa_hrpt_sync_cc",
 	     gr_make_io_signature(1, 1, sizeof(gr_complex)),
 	     gr_make_io_signature(1, 1, sizeof(gr_complex))),
-    d_alpha(alpha), d_beta(beta), d_sps(sps), d_max_offset(max_offset),
-    d_phase(0.0), d_freq(0.0)
+    d_alpha(alpha), d_beta(beta), 
+    d_sps(sps), d_max_offset(max_offset),
+    d_phase(0.0), d_freq(1.0/sps),
+    d_last_sign(1)
 {
 }
 
@@ -54,7 +61,25 @@ noaa_hrpt_sync_cc::general_work(int noutput_items,
 
   int i = 0, j = 0;
   while (i < ninputs && j < noutput_items) {
-    out[j++] = in[i++];
+    float sample = in[i++].imag();
+    int sign = signum(sample);
+    d_phase += d_freq;
+
+    // Train on zero crossings in center region of symbol
+    if (sign != d_last_sign) {
+      if (d_phase > 0.25 && d_phase < 0.75) {
+	float phase_err = d_phase-0.5;
+	d_phase -= phase_err*d_alpha;        // 1st order phase adjustment
+	d_freq -= phase_err*d_beta;          // 2nd order frequency adjustment
+      }
+
+      d_last_sign = sign;
+    }
+
+    if (d_phase > 1.0) {
+      out[j++] = in[i];
+      d_phase -= 1.0;
+    }
   }
 
   consume_each(i);
diff --git a/gr-noaa/lib/noaa_hrpt_sync_cc.h b/gr-noaa/lib/noaa_hrpt_sync_cc.h
index f5b23ccaf..6abbcad48 100644
--- a/gr-noaa/lib/noaa_hrpt_sync_cc.h
+++ b/gr-noaa/lib/noaa_hrpt_sync_cc.h
@@ -42,6 +42,7 @@ class noaa_hrpt_sync_cc : public gr_block
   float d_max_offset;		// Maximum frequency offset for d_sps, samples/symbol
   float d_phase;		// Instantaneous symbol phase
   float d_freq;			// Instantaneous symbol frequency, samples/symbol
+  int   d_last_sign;            // Tracks zero crossings
 
  public:
   int general_work(int noutput_items,