Merging ofdm2 branch -r7047:7321 into trunk. This updates the OFDM code to hier_block2 in blks2impl and removed from blksimpl. The new code

implements a decision feedback sync loop to lock the phase/freq, removes two unnecessary premables and performs frame sync and equalization off 
single preamble symbol. Also adds/updates Python plotting tools and a branchless clip algorithm in gr_math.h.



git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@7324 221aa14e-8319-0410-a670-987f0aec2ac5

1 files changed, 165 insertions, 0 deletions

diff --git a/gnuradio-core/src/utils/gr_plot_char.py b/gnuradio-core/src/utils/gr_plot_char.py
new file mode 100755
index 000000000..6f799cdd2
--- /dev/null
+++ b/gnuradio-core/src/utils/gr_plot_char.py
@@ -0,0 +1,165 @@
+#!/usr/bin/env python
+#
+# Copyright 2007 Free Software Foundation, Inc.
+# 
+# This file is part of GNU Radio
+# 
+# GNU Radio 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.
+# 
+# GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+# 
+
+import scipy
+from pylab import *
+from optparse import OptionParser
+
+matplotlib.interactive(True)
+matplotlib.use('TkAgg')
+
+class draw_fft_c:
+    def __init__(self, filename, options):
+        self.hfile = open(filename, "r")
+        self.block_length = options.block
+        self.start = options.start
+        self.sample_rate = options.sample_rate
+
+        self.axis_font_size = 16
+        self.label_font_size = 18
+        self.title_font_size = 20
+        self.text_size = 22
+
+        # Setup PLOT
+        self.fig = figure(1, figsize=(16, 9), facecolor='w')
+        rcParams['xtick.labelsize'] = self.axis_font_size
+        rcParams['ytick.labelsize'] = self.axis_font_size
+        
+        self.text_file     = figtext(0.10, 0.94, ("File: %s" % filename), weight="heavy", size=self.text_size)
+        self.text_file_pos = figtext(0.10, 0.88, "File Position: ", weight="heavy", size=self.text_size)
+        self.text_block    = figtext(0.40, 0.88, ("Block Size: %d" % self.block_length),
+                                     weight="heavy", size=self.text_size)
+        self.text_sr       = figtext(0.60, 0.88, ("Sample Rate: %.2f" % self.sample_rate),
+                                     weight="heavy", size=self.text_size)
+        self.make_plots()
+
+        self.button_left_axes = self.fig.add_axes([0.45, 0.01, 0.05, 0.05], frameon=True)
+        self.button_left = Button(self.button_left_axes, "<")
+        self.button_left_callback = self.button_left.on_clicked(self.button_left_click)
+
+        self.button_right_axes = self.fig.add_axes([0.50, 0.01, 0.05, 0.05], frameon=True)
+        self.button_right = Button(self.button_right_axes, ">")
+        self.button_right_callback = self.button_right.on_clicked(self.button_right_click)
+
+        self.xlim = self.sp_f.get_xlim()
+
+        self.manager = get_current_fig_manager()
+        connect('key_press_event', self.click)
+        show()
+        
+    def get_data(self):
+        self.text_file_pos.set_text("File Position: %d" % (self.hfile.tell()))
+        f = scipy.fromfile(self.hfile, dtype=scipy.int8, count=self.block_length)
+        #print "Read in %d items" % len(self.f)
+        if(len(f) == 0):
+            print "End of File"
+        else:
+            self.f = f
+            self.time = [i*(1/self.sample_rate) for i in range(len(self.f))]
+        
+    def make_plots(self):
+        # if specified on the command-line, set file pointer
+        self.hfile.seek(8*self.start, 1)
+
+        self.get_data()
+        
+        # Subplot for real and imaginary parts of signal
+        self.sp_f = self.fig.add_subplot(2,1,1, position=[0.075, 0.2, 0.875, 0.6])
+        self.sp_f.set_title(("Amplitude"), fontsize=self.title_font_size, fontweight="bold")
+        self.sp_f.set_xlabel("Time (s)", fontsize=self.label_font_size, fontweight="bold")
+        self.sp_f.set_ylabel("Amplitude (V)", fontsize=self.label_font_size, fontweight="bold")
+        self.plot_f = plot(self.time, self.f, 'bo-')
+        self.sp_f.set_ylim([1.5*min(self.f),
+                            1.5*max(self.f)])
+
+        draw()
+
+    def update_plots(self):
+        self.plot_f[0].set_data([self.time, self.f])
+        self.sp_f.set_ylim([1.5*min(self.f),
+                            1.5*max(self.f)])
+        draw()
+        
+    def click(self, event):
+        forward_valid_keys = [" ", "down", "right"]
+        backward_valid_keys = ["up", "left"]
+
+        if(find(event.key, forward_valid_keys)):
+            self.step_forward()
+            
+        elif(find(event.key, backward_valid_keys)):
+            self.step_backward()
+
+    def button_left_click(self, event):
+        self.step_backward()
+
+    def button_right_click(self, event):
+        self.step_forward()
+
+    def step_forward(self):
+        self.get_data()
+        self.update_plots()
+
+    def step_backward(self):
+        # Step back in file position
+        if(self.hfile.tell() >= 2*self.block_length ):
+            self.hfile.seek(-2*self.block_length, 1)
+        else:
+            self.hfile.seek(-self.hfile.tell(),1)
+        self.get_data()
+        self.update_plots()
+        
+            
+
+#FIXME: there must be a way to do this with a Python builtin
+def find(item_in, list_search):
+    for l in list_search:
+        if item_in == l:
+            return True
+    return False
+
+def main():
+    usage="%prog: [options] input_filename"
+    description = "Takes a GNU Radio floating point binary file and displays the samples versus time. You can set the block size to specify how many points to read in at a time and the start position in the file. By default, the system assumes a sample rate of 1, so in time, each sample is plotted versus the sample number. To set a true time axis, set the sample rate (-R or --sample-rate) to the sample rate used when capturing the samples."
+
+    parser = OptionParser(conflict_handler="resolve", usage=usage, description=description)
+    parser.add_option("-B", "--block", type="int", default=1000,
+                      help="Specify the block size [default=%default]")
+    parser.add_option("-s", "--start", type="int", default=0,
+                      help="Specify where to start in the file [default=%default]")
+    parser.add_option("-R", "--sample-rate", type="float", default=1.0,
+                      help="Set the sampler rate of the data [default=%default]")
+    
+    (options, args) = parser.parse_args ()
+    if len(args) != 1:
+        parser.print_help()
+        raise SystemExit, 1
+    filename = args[0]
+
+    dc = draw_fft_c(filename, options)
+
+if __name__ == "__main__":
+    try:
+        main()
+    except KeyboardInterrupt:
+        pass
+