[Discuss-gnuradio] GMSK demod

[M. Awais Arshad]

hi,

    I am trying to demodulate GSM signals and captured some live GSM data using rfx900 on usrp. After running my code i encountered these following errors:

address@hidden:~$ python '/home/gohar/Desktop/gsm.py' 

>>> gr_fir_ccf: using SSE

Traceback (most recent call last):

File  line 90, in <module>    my_top_block().run()

File line 81, in __init__    omega_relative_limit = 0)

TypeError: __init__() got multiple values for keyword argument 'gain_mu'

The first one is regarding the FIR filter which i am using ,,, i dont know the reason for this error "  gr_fir_ccf: using SSE "  ,  as in other codes it has been used in the same way as i did: the same is also the case for my_top_block().run() and gmsk.demod() .  The python code is as fellows: 

from gnuradio import gr, usrp, db_dbs_rx, blks2

from gnuradio import audio

from gnuradio.eng_option import eng_option

from optparse import OptionParser

from gnuradio.blks2impl import gmsk

from usrpm import usrp_dbid

import sys

# constant

gsm_rate = 1625000.0 / 6.0

# script constant

decim = 112

gain = 10

# bts channel

c0 = 900.4e6

class my_top_block(gr.top_block):

    def __init__(self):

                gr.top_block.__init__(self)

         u = usrp.source_c(decim_rate = decim)

                s = usrp.pick_subdev(u, (usrp_dbid.TV_RX,

                                usrp_dbid.TV_RX_REV_2,

usrp_dbid.TV_RX_REV_3,

                                usrp_dbid.BASIC_RX))

                u.set_mux(usrp.determine_rx_mux_value(u, s))

subdev = usrp.selected_subdev(u, s)

                if subdev.dbid() is None:

raise Exception('dbs daughterboard yyy not detected!')

subdev.set_gain(gain)

sps = u.adc_freq() / u.decim_rate()

if sps < 2 * gsm_rate:

raise Exception('sample rate too low')

u.tune(0, subdev, c0 )

xcf = 150e3

xtw = 50e3

xt = gr.firdes.low_pass(1.0, sps, xcf, xtw,

  gr.firdes.WIN_HAMMING)

xf = gr.fir_filter_ccf(1, xt)

gd = gmsk.gmsk_demod(self, sps / gsm_rate, gain_mu = 0.01,

    omega_relative_limit = 0.05)

                g = gr.file_sink(gr.sizeof_gr_complex,data) 

                self.connect(u, xf, gd,g)

 

            

if __name__ == '__main__':

    try:

        my_top_block().run()

    except KeyboardInterrupt:

        pass

#####################################################

I will be very grateful if anyone can give me some advice to solve these problems.

Thanks.