atsc-blade.py

#!/usr/bin/env /usr/bin/python

# Copyright 2013 Clayton Smith (argilo@gmail.com)
# Copyright 2014 Ryan Tucker (rtucker@gmail.com)
#   (Add UDP streaming support, tweak RRC filter)
#
# This program 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 of the License, or
# (at your option) any later version.
#
# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

from gnuradio import gr, atsc, blocks, analog, filter
from gnuradio.filter import firdes
from grc_gnuradio import blks2 as grc_blks2
import sys, os
import osmosdr

UDP_HOST="0.0.0.0"
UDP_PORT=1234

TAPS=100

def main(args):
    nargs = len(args)
    if nargs == 1:
        infile  = args[0]
        outfile = None
        print("Transmitting pre-encoded content: %s" % infile)
    elif nargs == 2:
        infile  = args[0]
        outfile  = args[1]
        print("Converting pre-encoded content to complex baseband: %s -> %s" % (infile, outfile))
    else:
        infile = None
        outfile = None
        print("Listening on %s port %d/udp" % (UDP_HOST, UDP_PORT))

    symbol_rate = 4500000.0 / 286 * 684
    pilot_freq = 309441
    center_freq = 473000000
    txvga1_gain = -6
    txvga2_gain = 12

    tb = gr.top_block()

    if infile is not None:
        src = blocks.file_source(gr.sizeof_char, infile, False if outfile else True)
    else:
        src = blocks.udp_source(gr.sizeof_char, UDP_HOST, UDP_PORT)

    pad = atsc.pad()
    rand = atsc.randomizer()
    rs_enc = atsc.rs_encoder()
    inter = atsc.interleaver()
    trell = atsc.trellis_encoder()
    fsm = atsc.field_sync_mux()

    v2s = blocks.vector_to_stream(gr.sizeof_char, 1024)
    minn = blocks.keep_m_in_n(gr.sizeof_char, 832, 1024, 4)
    b2f = blocks.uchar_to_float()
    mul = blocks.multiply_const_vff((2, ))
    add = blocks.add_const_vff((-7 + 1.25, ))
    zero = analog.sig_source_f(0, analog.GR_CONST_WAVE, 0, 0, 0)
    #rrc = filter.fir_filter_ccf(1, firdes.root_raised_cosine(0.1, symbol_rate, symbol_rate/2, 0.1152, TAPS))
    rrc = filter.fft_filter_ccc(1, firdes.root_raised_cosine(0.1, symbol_rate, symbol_rate/2, 0.1152, TAPS))
    offset = analog.sig_source_c(symbol_rate, analog.GR_COS_WAVE, -3000000 + pilot_freq, 0.9, 0)
    mix = blocks.multiply_vcc(1)
    f2c = blocks.float_to_complex(1)

    tb.connect(src, pad, rand, rs_enc, inter, trell, fsm, v2s, minn, b2f, mul, add)
    tb.connect((add, 0), (f2c, 0))
 
    tb.connect((zero, 0), (f2c, 1))
    tb.connect((f2c, 0), (mix, 0))
    tb.connect((offset, 0), (mix, 1))


    if outfile:
        dst = blocks.file_sink(gr.sizeof_gr_complex, outfile)
        tb.connect(mix, rrc, dst)
    else:
        out = osmosdr.sink(args="bladerf=0,buffers=128,buflen=16384")
        out.set_sample_rate(symbol_rate)
        out.set_center_freq(center_freq, 0)
        out.set_freq_corr(0, 0)
        out.set_gain(txvga2_gain, 0)
        out.set_bb_gain(txvga1_gain, 0)
        out.set_bandwidth(6000000, 0)
        tb.connect(mix, rrc, out)

    tb.run()


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