Merged -r3690:3730 from jcorgan/pager branch into trunk.

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@3731 221aa14e-8319-0410-a670-987f0aec2ac5

11 files changed, 339 insertions, 63 deletions

diff --git a/gr-pager/README b/gr-pager/README
index 9c0701d9f..4327f258e 100644
--- a/gr-pager/README
+++ b/gr-pager/README
@@ -1,13 +1,12 @@
 This GNU Radio component implements (will implement) common radiopager
 signaling protocols such as POCSAG and FLEX.
 
-Current status (9/28/06):
+Current status (10/6/06):
 
-FLEX receiving is nearing completion.
+FLEX receiving is completed except for addition of BCH error correction.
 
 pager.slicer_fb()         Accepts a complex baseband downconverted channel 
                           and outputs 4-level FSK symbols [0-3] as bytes.
-			  This may migrate into gnuradio-core at some point.
 
 pager.flex_sync()	  Accepts 4FSK symbol stream at channel rate and
 			  outputs four phases of FLEX data bits as bytes.
@@ -20,10 +19,8 @@ pager.flex_deinterleave() Accepts a single phase of FLEX data bits and performs
 			  and converted into FLEX data words for output.
 
 pager.flex_parse()	  Sink block that accepts a single phase of FLEX data 
-			  words and unpacks and parses individual pages.
-			  Currently, this block decodes the capcodes of each
-			  receive page and displays the page type, but not yet
-			  the contents.
+			  words and unpacks and parses individual pages. These are 
+			  passed outside the data plane via gr_message's.
 
 pager.flex_decode()       Combines the above blocks correctly to convert
                           from downconverted baseband to pager messages
@@ -33,5 +30,8 @@ usrp_flex.py              Instantiates USRP receive chain to receive FLEX
 			  Right now this installs into $PREFIX/bin but will
                           probably make it into gnuradio-examples.
 
+aypabtu.py		  Decodes FLEX pages from multiple rx channels in a range.
+		          Incomplete.
+
 Johnathan Corgan
 jcorgan@aeinet.com
diff --git a/gr-pager/src/Makefile.am b/gr-pager/src/Makefile.am
index c4a8c938e..e8dce780c 100644
--- a/gr-pager/src/Makefile.am
+++ b/gr-pager/src/Makefile.am
@@ -28,8 +28,9 @@ TESTS = \
     run_tests
 
 bin_SCRIPTS = \
-    usrp_flex.py
-
+    usrp_flex.py \
+    aypabtu.py 
+    
 noinst_PYTHON = \
     qa_pager.py
 
@@ -46,7 +47,8 @@ SWIGPYTHONARGS = $(SWIGPYTHONFLAGS) $(STD_DEFINES_AND_INCLUDES)
 
 ALL_IFILES = \
     $(LOCAL_IFILES) \
-    $(NON_LOCAL_IFILES)		
+    $(NON_LOCAL_IFILES)	\
+    pager_flex_frame.i
 
 NON_LOCAL_IFILES = \
     $(GNURADIO_I)
@@ -67,13 +69,15 @@ ourpython_PYTHON = \
     __init__.py \
     pager_swig.py \
     flex_demod.py \
-    usrp_flex.py
-
+    usrp_flex.py \
+    aypabtu.py
+    
 ourlib_LTLIBRARIES = _pager_swig.la
 
 # These are the source files that go into the shared library
 _pager_swig_la_SOURCES = \
     pager_swig.cc \
+    pager_flex_frame.cc \
     pager_slicer_fb.cc \
     pager_flex_sync.cc \
     pager_flex_deinterleave.cc \
diff --git a/gr-pager/src/aypabtu.py b/gr-pager/src/aypabtu.py
new file mode 100755
index 000000000..c742744c3
--- /dev/null
+++ b/gr-pager/src/aypabtu.py
@@ -0,0 +1,117 @@
+#!/usr/bin/env python
+
+from math import pi
+from gnuradio import gr, gru, usrp, optfir, audio, eng_notation, blks, pager
+from gnuradio.eng_option import eng_option
+from optparse import OptionParser
+from string import split, join, printable
+
+class usrp_source_c(gr.hier_block):
+    """
+    Create a USRP source object supplying complex floats.
+    
+    Selects user supplied subdevice or chooses first available one.
+
+    Calibration value is the offset from the tuned frequency to 
+    the actual frequency.       
+    """
+    def __init__(self, fg, subdev_spec, decim, gain=None, calibration=0.0):
+        self._decim = decim
+        self._src = usrp.source_c()
+        if subdev_spec is None:
+            subdev_spec = usrp.pick_rx_subdevice(self._src)
+        self._subdev = usrp.selected_subdev(self._src, subdev_spec)
+        self._src.set_mux(usrp.determine_rx_mux_value(self._src, subdev_spec))
+        self._src.set_decim_rate(self._decim)
+
+        # If no gain specified, set to midrange
+        if gain is None:
+            g = self._subdev.gain_range()
+            gain = (g[0]+g[1])/2.0
+
+        self._subdev.set_gain(gain)
+        self._cal = calibration
+
+        gr.hier_block.__init__(self, fg, self._src, self._src)
+
+    def tune(self, freq):
+        result = usrp.tune(self._src, 0, self._subdev, freq+self._cal)
+        # TODO: deal with residual
+
+    def rate(self):
+        return self._src.adc_rate()/self._decim
+
+class channelizer(blks.analysis_filterbank):
+    def __init__(self,
+		 fg,		# Flow graph
+		 if_rate,	# IF input sample rate (complex)
+		 channel_rate,	# Final channel sample rate (complex)
+		 channel_pass,	# Occupied spectrum for narrowband channel
+		 channel_stop):	# Total channel + guard band
+
+        num_channels = int(if_rate/channel_rate)
+        taps = optfir.low_pass(1.0, if_rate, channel_pass, channel_stop, 0.1, 60)
+        blks.analysis_filterbank.__init__(self, fg, num_channels, taps)
+
+class app_flow_graph(gr.flow_graph):
+    def __init__(self, options, args, queue):
+	gr.flow_graph.__init__(self)
+	self.options = options
+	self.args = args
+
+	# FIXME: Parameterize
+	#
+	# Difference between upper and lower must evenly divide into USRP sample rate
+	# and also must be divisible by 25000
+	options.channel_rate =     25000
+        options.channel_pass =      8000
+        options.channel_stop =     10000
+        	
+	if_rate = options.upper_freq - options.lower_freq
+	center_freq = options.lower_freq + if_rate/2
+	num_channels = int(if_rate/options.channel_rate)
+	decim = int(64000000/if_rate)
+		
+	self.SRC = usrp_source_c(self, options.rx_board, decim, options.gain, options.calibration)
+        self.CHAN = channelizer(self, if_rate, options.channel_rate, options.channel_pass, options.channel_stop)
+
+        self.connect(self.SRC, self.CHAN)
+	for i in range(num_channels):
+	    freq = options.lower_freq + i*options.channel_rate
+	    if freq > center_freq:
+		freq -= if_rate/2
+	    else:
+		freq += if_rate/2
+            FLEX = pager.flex_demod(self, options.channel_rate, queue)
+	    self.connect((self.CHAN, i), FLEX.INPUT)
+
+	self.SRC.tune(center_freq)
+
+def make_printable(data):
+    return "".join(char for char in data if char in printable)
+
+def main():
+    parser = OptionParser(option_class=eng_option)
+    parser.add_option("",   "--upper-freq",   type="eng_float", help="lower Rx frequency", metavar="LOWER")
+    parser.add_option("",   "--lower-freq",   type="eng_float", help="upper Rx frequency", metavar="UPPER")
+    parser.add_option("-R", "--rx-board",     type="subdev", help="select USRP Rx side A or B (default=first daughterboard found)", metavar="SIDE")
+    parser.add_option("-c", "--calibration",  type="eng_float", default=0.0, help="set frequency offset to Hz", metavar="Hz")
+    parser.add_option("-g", "--gain", 	    type="int", help="set RF gain", metavar="dB")
+    (options, args) = parser.parse_args()
+
+    # FIXME: parameter sanity checks
+
+    queue = gr.msg_queue()
+    fg = app_flow_graph(options, args, queue)
+    try:
+        fg.start()
+	while 1:
+	    msg = queue.delete_head() # Blocking read
+	    fields = split(msg.to_string(), chr(128))
+	    print join([make_printable(field) for field in fields], '|')
+
+    except KeyboardInterrupt:
+        fg.stop()
+
+if __name__ == "__main__":
+    main()
diff --git a/gr-pager/src/flex_demod.py b/gr-pager/src/flex_demod.py
index 95a6517a1..a8c6f09b1 100644
--- a/gr-pager/src/flex_demod.py
+++ b/gr-pager/src/flex_demod.py
@@ -19,10 +19,12 @@
 # Boston, MA 02110-1301, USA.
 # 
 
-from gnuradio import gr, optfir
+from gnuradio import gr, gru, optfir, blks
 from math import pi
 import pager_swig
 
+chan_rate = 16000
+
 class flex_demod:
     """
     FLEX pager protocol demodulation block.
@@ -32,6 +34,7 @@ class flex_demod:
 
     Flow graph (so far):
 
+    RSAMP    - Resample incoming stream to 16000 sps
     QUAD     - Quadrature demodulator converts FSK to baseband amplitudes  
     LPF      - Low pass filter to remove noise prior to slicer
     SLICER   - Converts input to one of four symbols (0, 1, 2, 3)
@@ -45,28 +48,39 @@ class flex_demod:
     @type sample_rate: integer
     """
 
-    def __init__(self, fg, channel_rate):
-        k = channel_rate/(2*pi*4800)        # 4800 Hz max deviation
+
+    def __init__(self, fg, channel_rate, queue):
+        k = chan_rate/(2*pi*4800)        # 4800 Hz max deviation
         QUAD = gr.quadrature_demod_cf(k)
 	self.INPUT = QUAD
-		
-        taps = optfir.low_pass(1.0, channel_rate, 3200, 6400, 0.1, 60)
+			
+	if channel_rate != chan_rate:
+		interp = gru.lcm(channel_rate, chan_rate)/channel_rate
+		decim  = gru.lcm(channel_rate, chan_rate)/chan_rate
+		RESAMP = blks.rational_resampler_ccf(fg, interp, decim)
+		self.INPUT = RESAMP
+			
+        taps = optfir.low_pass(1.0, chan_rate, 3200, 6400, 0.1, 60)
         LPF = gr.fir_filter_fff(1, taps)
         SLICER = pager_swig.slicer_fb(.001, .00001) # Attack, decay
-	SYNC = pager_swig.flex_sync(channel_rate)
-        fg.connect(QUAD, LPF, SLICER, SYNC)
+	SYNC = pager_swig.flex_sync(chan_rate)
+
+	if channel_rate != chan_rate:
+            fg.connect(RESAMP, QUAD, LPF, SLICER, SYNC)
+	else:
+	    fg.connect(QUAD, LPF, SLICER, SYNC)
 
 	DEINTA = pager_swig.flex_deinterleave()
-	PARSEA = pager_swig.flex_parse()
+	PARSEA = pager_swig.flex_parse(queue)
 
 	DEINTB = pager_swig.flex_deinterleave()
-	PARSEB = pager_swig.flex_parse()
+	PARSEB = pager_swig.flex_parse(queue)
 
 	DEINTC = pager_swig.flex_deinterleave()
-	PARSEC = pager_swig.flex_parse()
+	PARSEC = pager_swig.flex_parse(queue)
 
 	DEINTD = pager_swig.flex_deinterleave()
-	PARSED = pager_swig.flex_parse()
+	PARSED = pager_swig.flex_parse(queue)
 	
 	fg.connect((SYNC, 0), DEINTA, PARSEA)
 	fg.connect((SYNC, 1), DEINTB, PARSEB)
diff --git a/gr-pager/src/pager.i b/gr-pager/src/pager.i
index aaa02feea..cc73a5473 100644
--- a/gr-pager/src/pager.i
+++ b/gr-pager/src/pager.i
@@ -25,6 +25,7 @@
 
 %{
 #include "gnuradio_swig_bug_workaround.h"	// mandatory bug fix
+#include "pager_flex_frame.h"
 #include "pager_slicer_fb.h"
 #include "pager_flex_sync.h"
 #include "pager_flex_deinterleave.h"
@@ -32,6 +33,8 @@
 #include <stdexcept>
 %}
 
+%include "pager_flex_frame.i"
+
 // ----------------------------------------------------------------
 
 GR_SWIG_BLOCK_MAGIC(pager,slicer_fb);
@@ -78,12 +81,12 @@ public:
 
 GR_SWIG_BLOCK_MAGIC(pager,flex_parse);
 
-pager_flex_parse_sptr pager_make_flex_parse();
+pager_flex_parse_sptr pager_make_flex_parse(gr_msg_queue_sptr queue);
 
 class pager_flex_parse : public gr_block
 {
 private:
-    pager_flex_parse();
+    pager_flex_parse(gr_msg_queue_sptr queue);
 
 public:
 };
diff --git a/gr-pager/src/pager_flex_frame.cc b/gr-pager/src/pager_flex_frame.cc
new file mode 100644
index 000000000..3934c7692
--- /dev/null
+++ b/gr-pager/src/pager_flex_frame.cc
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2006 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 2, 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#include <pager_flex_frame.h>
+
+pager_flex_frame_sptr pager_make_flex_frame()
+{
+    return pager_flex_frame_sptr(new pager_flex_frame());
+}
+
+pager_flex_frame::pager_flex_frame()
+{
+}
+
+pager_flex_frame::~pager_flex_frame()
+{
+}
diff --git a/gr-pager/src/pager_flex_frame.h b/gr-pager/src/pager_flex_frame.h
new file mode 100644
index 000000000..300de9096
--- /dev/null
+++ b/gr-pager/src/pager_flex_frame.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2006 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 2, 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.
+ */
+#ifndef INCLUDED_PAGER_FLEX_FRAME_H
+#define INCLUDED_PAGER_FLEX_FRAME_H
+
+#include <boost/shared_ptr.hpp>
+
+class pager_flex_frame;
+typedef boost::shared_ptr<pager_flex_frame> pager_flex_frame_sptr;
+
+/*!
+ * \brief public constructor for pager_flex_frame
+ */
+pager_flex_frame_sptr pager_make_flex_frame();
+
+/*!
+ * \brief flex_frame.
+ */
+class pager_flex_frame {
+    // Constructor is private to force use of shared_ptr
+    pager_flex_frame();
+    friend pager_flex_frame_sptr pager_make_flex_frame();
+
+public:
+    ~pager_flex_frame();
+};
+
+#endif /* INCLUDED_PAGER_FLEX_FRAME_H */
diff --git a/gr-pager/src/pager_flex_frame.i b/gr-pager/src/pager_flex_frame.i
new file mode 100644
index 000000000..d3fa1b6b7
--- /dev/null
+++ b/gr-pager/src/pager_flex_frame.i
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2006 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 2, 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.
+ */
+
+class pager_flex_frame;
+typedef boost::shared_ptr<pager_flex_frame> pager_flex_frame_sptr;
+%template(pager_flex_frame_sptr) boost::shared_ptr<pager_flex_frame>;
+
+%rename(flex_frame) pager_make_flex_frame;
+pager_flex_frame_sptr pager_make_flex_frame();
+
+/*!
+ * \brief flex_frame.
+ */
+class pager_flex_frame {
+    pager_flex_frame();
+
+public:
+};
+
diff --git a/gr-pager/src/pager_flex_parse.cc b/gr-pager/src/pager_flex_parse.cc
index 22ee9eeca..7178ba516 100644
--- a/gr-pager/src/pager_flex_parse.cc
+++ b/gr-pager/src/pager_flex_parse.cc
@@ -27,16 +27,18 @@
 #include <pageri_bch3221.h>
 #include <gr_io_signature.h>
 #include <ctype.h>
+#include <iostream>
 
-pager_flex_parse_sptr pager_make_flex_parse()
+pager_flex_parse_sptr pager_make_flex_parse(gr_msg_queue_sptr queue)
 {
-    return pager_flex_parse_sptr(new pager_flex_parse());
+    return pager_flex_parse_sptr(new pager_flex_parse(queue));
 }
 
-pager_flex_parse::pager_flex_parse() :
+pager_flex_parse::pager_flex_parse(gr_msg_queue_sptr queue) :
     gr_sync_block("flex_parse",
-    gr_make_io_signature(1, 1, sizeof(gr_int32)),
-    gr_make_io_signature(0, 0, 0))
+	gr_make_io_signature(1, 1, sizeof(gr_int32)),
+	gr_make_io_signature(0, 0, 0)),
+    d_queue(queue)
 {
     d_count = 0;
 }
@@ -128,7 +130,8 @@ void pager_flex_parse::parse_data()
 	if (mw1 > 87 || mw2 > 87)
 	    continue;				// Invalid offsets
 
-	printf("%010i: ", d_capcode);
+	d_payload.str("");
+	d_payload << d_capcode << FIELD_DELIM << d_type << FIELD_DELIM;
 
 	if (is_alphanumeric_page(d_type))
 	    parse_alphanumeric(mw1, mw2-1, j);
@@ -139,17 +142,19 @@ void pager_flex_parse::parse_data()
 	else
 	    parse_unknown(mw1, mw2);
 
-	printf("\n");
-	fflush(stdout);
+	//std::cout << d_payload.str() << std::endl;
+	//fflush(stdout);
+
+	gr_message_sptr msg = gr_make_message_from_string(std::string(d_payload.str()));
+	d_queue->handle(msg);
     }
 }
 
 void pager_flex_parse::parse_alphanumeric(int mw1, int mw2, int j)
 {
-
     int frag;
     bool cont;
-    
+
     if (!d_laddr) {
 	frag = (d_datawords[mw1] >> 11) & 0x03;
 	cont = (d_datawords[mw1] >> 10) & 0x01;
@@ -161,32 +166,31 @@ void pager_flex_parse::parse_alphanumeric(int mw1, int mw2, int j)
 	mw2--;
     }    
 
-    printf("%c F:%i C:%i|", d_type == FLEX_SECURE ? 'S' : 'A',
-	frag, cont);
+    d_payload << frag << FIELD_DELIM;
+    d_payload << cont << FIELD_DELIM;
 
     for (int i = mw1; i <= mw2; i++) {
 	gr_int32 dw = d_datawords[i];
+	unsigned char ch;
 	
 	if (i > mw1 || frag != 0x03) {
-	    unsigned char ch0 = dw & 0x7F;
-	    if (ch0 != 0x03)	// Fill
-		putchar(isprint(ch0) ? ch0 : '.');
+	    ch = dw & 0x7F;
+	    if (ch != 0x03)
+		d_payload << ch;
 	}
 	
-	unsigned char ch1 = (dw >> 7) & 0x7F;
-	if (ch1 != 0x03)	// Fill
-	    putchar(isprint(ch1) ? ch1 : '.');
-	
-	unsigned char ch2 = (dw >> 14) & 0x7F;
-	if (ch2 != 0x03)	// Fill
-	    putchar(isprint(ch2) ? ch2: '.');
+	ch = (dw >> 7) & 0x7F;
+	if (ch != 0x03)	// Fill
+	    d_payload << ch;
+	    	
+	ch = (dw >> 14) & 0x7F;
+	if (ch != 0x03)	// Fill
+	    d_payload << ch;
     }
 }
 
 void pager_flex_parse::parse_numeric(int mw1, int mw2, int j)
 {
-    printf("N        |");
-
     // Get first dataword from message field or from second
     // vector word if long address
     gr_int32 dw;
@@ -215,7 +219,7 @@ void pager_flex_parse::parse_numeric(int mw1, int mw2, int j)
 	    dw >>= 1;
     	    if (--count == 0) {
 		if (digit != 0x0C) // Fill
-		    putchar(flex_bcd[digit]);
+                    d_payload << flex_bcd[digit];
 		count = 4;
 	    }
 	}
@@ -226,10 +230,8 @@ void pager_flex_parse::parse_numeric(int mw1, int mw2, int j)
 
 void pager_flex_parse::parse_tone_only()
 {
-    printf("T        |");
 }
 
 void pager_flex_parse::parse_unknown(int mw1, int mw2)
 {
-    printf("U        |(unparsed)");
 }
diff --git a/gr-pager/src/pager_flex_parse.h b/gr-pager/src/pager_flex_parse.h
index 696eedc92..e5a225b28 100644
--- a/gr-pager/src/pager_flex_parse.h
+++ b/gr-pager/src/pager_flex_parse.h
@@ -23,24 +23,31 @@
 #define INCLUDED_PAGER_FLEX_PARSE_H
 
 #include <gr_sync_block.h>
+#include <gr_msg_queue.h>
 #include <pageri_flex_modes.h>
+#include <sstream>
 
 class pager_flex_parse;
 typedef boost::shared_ptr<pager_flex_parse> pager_flex_parse_sptr;
 
-pager_flex_parse_sptr pager_make_flex_parse();
+pager_flex_parse_sptr pager_make_flex_parse(gr_msg_queue_sptr queue);
 
 /*!
  * \brief flex parse description
  * \ingroup block
  */
 
+#define FIELD_DELIM ((unsigned char)128)
+
 class pager_flex_parse : public gr_sync_block
 {
 private:
     // Constructors
-    friend pager_flex_parse_sptr pager_make_flex_parse();
-    pager_flex_parse();
+    friend pager_flex_parse_sptr pager_make_flex_parse(gr_msg_queue_sptr queue);
+    pager_flex_parse(gr_msg_queue_sptr queue);
+
+    std::ostringstream d_payload;
+    gr_msg_queue_sptr d_queue;		  // Destination for decoded pages
 
     int d_count;	                  // Count of received codewords
     gr_int32 d_datawords[88];             // 11 blocks of 8 32-bit words
diff --git a/gr-pager/src/usrp_flex.py b/gr-pager/src/usrp_flex.py
index 636efc7e3..055583c99 100755
--- a/gr-pager/src/usrp_flex.py
+++ b/gr-pager/src/usrp_flex.py
@@ -4,6 +4,7 @@ from gnuradio import gr, gru, usrp, optfir, eng_notation, blks, pager
 from gnuradio.eng_option import eng_option
 from optparse import OptionParser
 import time, os, sys
+from string import split, join
 
 """
 This example application demonstrates receiving and demodulating the
@@ -68,21 +69,21 @@ class usrp_source_c(gr.hier_block):
         return self._src.adc_rate()/self._decim
 
 class app_flow_graph(gr.flow_graph):
-    def __init__(self, options, args):
+    def __init__(self, options, args, queue):
         gr.flow_graph.__init__(self)
         self.options = options
         self.args = args
 
         USRP = usrp_source_c(self,          # Flow graph
                     options.rx_subdev_spec, # Daugherboard spec
-	            250,                    # IF decimation ratio gets 256K if_rate
+	            256,                    # IF decimation ratio gets 250K if_rate
                     options.gain,           # Receiver gain
                     options.calibration)    # Frequency offset
         USRP.tune(options.frequency)
 
         if_rate = USRP.rate()
-        channel_rate = 32000                # Oversampled by 10 or 20
-        channel_decim = if_rate // channel_rate
+        channel_rate = 25000                
+        channel_decim = int(if_rate / channel_rate)
 	
         CHAN_taps = optfir.low_pass(1.0,          # Filter gain
                                     if_rate,      # Sample rate
@@ -101,7 +102,7 @@ class app_flow_graph(gr.flow_graph):
                         1.0,               # Initial gain
                         1.0)               # Maximum gain
 	
-        FLEX = pager.flex_demod(self, 32000)      
+        FLEX = pager.flex_demod(self, 25000, queue)
 
         self.connect(USRP, CHAN, AGC, FLEX.INPUT)
 	
@@ -120,11 +121,18 @@ def main():
     if options.frequency < 1e6:
 	options.frequency *= 1e6
 	
-    fg = app_flow_graph(options, args)
+    queue = gr.msg_queue()
+
+    fg = app_flow_graph(options, args, queue)
     try:
-        fg.run()
+        fg.start()
+	while 1:
+	    msg = queue.delete_head() # Blocking read
+	    fields = split(msg.to_string(), chr(128))
+	    print join(fields, '|')
+
     except KeyboardInterrupt:
-        pass
+        fg.stop()
 
 if __name__ == "__main__":
     main()