Corrected precision of FCCH search function

1 files changed, 122 insertions, 0 deletions

diff --git a/src/python/gsm_findfcch_usrp.py b/src/python/gsm_findfcch_usrp.py
new file mode 100755
index 0000000..7bf81f3
--- /dev/null
+++ b/src/python/gsm_findfcch_usrp.py
@@ -0,0 +1,122 @@
+#!/usr/bin/env python
+#!/usr/bin/env python
+
+from gnuradio import gr, gru, blks2
+from gnuradio import usrp
+#from gnuradio import gsm
+from gnuradio.eng_option import eng_option
+from optparse import OptionParser
+from os import sys
+#"""
+for extdir in ['../../debug/src/lib','../../debug/src/lib/.libs']:
+    if extdir not in sys.path:
+        sys.path.append(extdir)
+import gsm                        
+#"""
+def pick_subdevice(u):
+    if u.db[0][0].dbid() >= 0:
+        return (0, 0)
+    if u.db[1][0].dbid() >= 0:
+        return (1, 0)
+    return (0, 0)
+
+class gsm_receiver_first_blood(gr.top_block):
+    def __init__(self):
+        gr.top_block.__init__(self)
+        ( self.options, self.args) = self._przetworz_opcje()
+        self._ustaw_taktowanie()
+        self.zrodlo = self._ustaw_zrodlo()
+        self.filtr = self._ustaw_filtr()
+        self.interpolator = self._ustaw_interpolator()
+        self.odbiornik = self._ustaw_odbiornik()
+        self.konwerter = self._ustaw_konwerter()
+        self.ujscie = self._ustaw_ujscie()
+    
+        self.connect(self.zrodlo, self.filtr,  self.interpolator, self.odbiornik, self.konwerter, self.ujscie)
+#       self.connect(self.zrodlo, self.ujscie)
+  
+    def _ustaw_ujscie(self):
+        nazwa_pliku_wy = self.options.outputfile
+        ujscie = gr.file_sink(gr.sizeof_float, nazwa_pliku_wy)
+        return ujscie
+    
+    def _ustaw_zrodlo(self):	
+        options = self.options
+        fusb_block_size = gr.prefs().get_long('fusb', 'block_size', 4096)
+        fusb_nblocks    = gr.prefs().get_long('fusb', 'nblocks', 16)
+        self.usrp = usrp.source_c(decim_rate=options.decim, fusb_block_size=fusb_block_size, fusb_nblocks=fusb_nblocks)
+        
+        if options.rx_subdev_spec is None:
+            options.rx_subdev_spec = pick_subdevice(self.usrp)
+        
+        self.usrp.set_mux(usrp.determine_rx_mux_value(self.usrp, options.rx_subdev_spec))
+        # determine the daughterboard subdevice
+        self.subdev = usrp.selected_subdev(self.usrp, options.rx_subdev_spec)
+        input_rate = self.usrp.adc_freq() / self.usrp.decim_rate()
+
+        # set initial values
+        if options.gain is None:
+            # if no gain was specified, use the mid-point in dB
+            g = self.subdev.gain_range()
+            options.gain = float(g[0]+g[1])/2
+
+        r = self.usrp.tune(0, self.subdev, options.freq)
+        self.subdev.set_gain(options.gain)
+        return self.usrp
+    
+    def _ustaw_taktowanie(self):
+        options = self.options
+        clock_rate = 64e6
+        self.clock_rate = clock_rate
+        self.input_rate = clock_rate / options.decim
+        self.gsm_symb_rate = 1625000.0 / 6.0
+        self.sps = self.input_rate / self.gsm_symb_rate
+
+    def _ustaw_filtr(self):
+        filter_cutoff   = 145e3	
+        filter_t_width  = 10e3
+        offset = 0
+        print "input_rate:", self.input_rate, "sample rate:", self.sps, " filter_cutoff:", filter_cutoff, " filter_t_width:", filter_t_width
+        filter_taps     = gr.firdes.low_pass(1.0, self.input_rate, filter_cutoff, filter_t_width, gr.firdes.WIN_HAMMING)
+        filtr          = gr.freq_xlating_fir_filter_ccf(1, filter_taps, offset, self.input_rate)
+        return filtr
+
+    def _ustaw_konwerter(self):
+        v2s = gr.vector_to_stream(gr.sizeof_float, 142)
+        return v2s
+    
+    def _ustaw_interpolator(self):
+        interpolator = gr.fractional_interpolator_cc(0, self.sps) 
+        return interpolator
+    
+    def _ustaw_odbiornik(self):
+        odbiornik = gsm.receiver_cf(1)
+        return odbiornik
+    
+    def _przetworz_opcje(self):
+        parser = OptionParser(option_class=eng_option)
+        parser.add_option("-d", "--decim", type="int", default=128,
+                                    help="Set USRP decimation rate to DECIM [default=%default]")
+        parser.add_option("-I", "--inputfile", type="string", default="cfile",
+                                    help="Input filename")
+        parser.add_option("-O", "--outputfile", type="string", default="cfile2.out",
+                                    help="Output filename")
+        parser.add_option("-R", "--rx-subdev-spec", type="subdev", default=None,
+                                    help="Select USRP Rx side A or B (default=first one with a daughterboard)")   
+        parser.add_option("-f", "--freq", type="eng_float", default="950.4M",
+                                    help="set frequency to FREQ", metavar="FREQ")
+        parser.add_option("-g", "--gain", type="eng_float", default=None,
+                                    help="Set gain in dB (default is midpoint)")
+        (options, args) = parser.parse_args ()
+        return (options, args)
+
+def main():
+    try:
+        gsm_receiver_first_blood().run()
+    except KeyboardInterrupt:
+        pass
+
+if __name__ == '__main__':
+    main()
+
+