#!/usr/bin/env python
#
# Copyright 2004 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., 59 Temple Place - Suite 330,
# Boston, MA 02111-1307, USA.
# 

from gnuradio import gr
from gnuradio import usrp
from gnuradio.eng_option import eng_option
import sys

def build_graph (filename, IF_freq, decim_rate, sample_count):

    fg = gr.flow_graph ()

    # 256K sample rate
    adc_rate = 64e6
    decim = decim_rate

    mux = 0xf0f0f0f0

    src = usrp.source_c (0, decim, 1, mux)
    src.set_rx_freq (0, -IF_freq)
    src.set_pga (0, 20)

    dst = gr.file_sink (gr.sizeof_gr_complex, filename)

    head = gr.head(gr.sizeof_gr_complex, sample_count)

    fg.connect(src, head, dst)

    return fg

def main (args):
    nargs = len (args)
    if nargs == 4:
        filename = args[0]
        IF_freq_hz = float (args[1]) * 1e6
        decim_rate = int (args[2])
        samples = int(float(args[3]) * 64e6 / float(decim_rate))
    else:
        sys.stderr.write ("usage: capture_to_file file_name IF_freq_MHz decim_rate duration_seconds\n")
        sys.exit (1)

    print "Capturing ", samples, " samples"

    fg = build_graph (filename, IF_freq_hz, decim_rate, samples)
    fg.run()

if __name__ == '__main__':
    main (sys.argv[1:])