diff options
Diffstat (limited to 'grc/src/grc_gnuradio/blks2/error_rate.py')
| -rw-r--r-- | grc/src/grc_gnuradio/blks2/error_rate.py | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/grc/src/grc_gnuradio/blks2/error_rate.py b/grc/src/grc_gnuradio/blks2/error_rate.py new file mode 100644 index 000000000..eb09940cb --- /dev/null +++ b/grc/src/grc_gnuradio/blks2/error_rate.py @@ -0,0 +1,138 @@ +# Copyright 2008 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 3, 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. +# + +default_win_size = 1000 + +from gnuradio import gr +import gnuradio.gr.gr_threading as _threading +import numpy + +#generate 1s counts array +_1s_counts = [sum([1&(i>>j) for j in range(8)]) for i in range(2**8)] + +class input_watcher(_threading.Thread): + """ + Read samples from the message queue and hand them to the callback. + """ + + def __init__(self, msgq, callback): + self._msgq = msgq + self._callback = callback + _threading.Thread.__init__(self) + self.setDaemon(1) + self.keep_running = True + self.start() + + def run(self): + r = '' + while True: + msg = self._msgq.delete_head() + itemsize = int(msg.arg1()) + nitems = int(msg.arg2()) + s = r + msg.to_string() + i = (nitems-nitems%2)*itemsize + r = s[i:] + s = s[:i] + samples = numpy.fromstring(s, numpy.int8) + self._callback(samples) + +class error_rate(gr.hier_block2): + """ + Sample the incoming data streams (byte) and calculate the bit or symbol error rate. + Write the running rate to the output data stream (float). + """ + + def __init__(self, type='BER', win_size=default_win_size, bits_per_symbol=2): + """! + Error rate constructor. + @param type a string 'BER' or 'SER' + @param win_size the number of samples to calculate over + @param bits_per_symbol the number of information bits per symbol (BER only) + """ + #init + gr.hier_block2.__init__( + self, 'error_rate', + gr.io_signature(2, 2, gr.sizeof_char), + gr.io_signature(1, 1, gr.sizeof_float), + ) + assert type in ('BER', 'SER') + self._max_samples = win_size + self._bits_per_symbol = bits_per_symbol + #setup message queue + msg_source = gr.message_source(gr.sizeof_float, 1) + self._msgq_source = msg_source.msgq() + msgq_sink = gr.msg_queue(2) + msg_sink = gr.message_sink(gr.sizeof_char, msgq_sink, False) #False -> blocking + inter = gr.interleave(gr.sizeof_char) + #start thread + self._num_errs = 0 + self._err_index = 0 + self._num_samps = 0 + self._err_array = numpy.zeros(self._max_samples, numpy.int8) + if type == 'BER': + input_watcher(msgq_sink, self._handler_ber) + elif type == 'SER': + input_watcher(msgq_sink, self._handler_ser) + #connect + self.connect(msg_source, self) + self.connect((self, 0), (inter, 0)) + self.connect((self, 1), (inter, 1)) + self.connect(inter, msg_sink) + + def _handler_ber(self, samples): + num = len(samples)/2 + arr = numpy.zeros(num, numpy.float32) + for i in range(num): + old_err = self._err_array[self._err_index] + #record error + self._err_array[self._err_index] = _1s_counts[samples[i*2] ^ samples[i*2 + 1]] + self._num_errs = self._num_errs + self._err_array[self._err_index] - old_err + #increment index + self._err_index = (self._err_index + 1)%self._max_samples + self._num_samps = min(self._num_samps + 1, self._max_samples) + #write sample + arr[i] = float(self._num_errs)/float(self._num_samps*self._bits_per_symbol) + #write message + msg = gr.message_from_string(arr.tostring(), 0, gr.sizeof_float, num) + self._msgq_source.insert_tail(msg) + + def _handler_ser(self, samples): + num = len(samples)/2 + arr = numpy.zeros(num, numpy.float32) + for i in range(num): + old_err = self._err_array[self._err_index] + #record error + ref = samples[i*2] + res = samples[i*2 + 1] + if ref == res: + self._err_array[self._err_index] = 0 + else: + self._err_array[self._err_index] = 1 + #update number of errors + self._num_errs = self._num_errs + self._err_array[self._err_index] - old_err + #increment index + self._err_index = (self._err_index + 1)%self._max_samples + self._num_samps = min(self._num_samps + 1, self._max_samples) + #write sample + arr[i] = float(self._num_errs)/float(self._num_samps) + #write message + msg = gr.message_from_string(arr.tostring(), 0, gr.sizeof_float, num) + self._msgq_source.insert_tail(msg) + |