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Diffstat (limited to 'gnuradio-core/src/python/gnuradio/blks2impl/logpwrfft.py')
-rw-r--r-- | gnuradio-core/src/python/gnuradio/blks2impl/logpwrfft.py | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/logpwrfft.py b/gnuradio-core/src/python/gnuradio/blks2impl/logpwrfft.py new file mode 100644 index 000000000..6f7fc520f --- /dev/null +++ b/gnuradio-core/src/python/gnuradio/blks2impl/logpwrfft.py @@ -0,0 +1,155 @@ +# +# 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. +# + +from gnuradio import gr, window +from stream_to_vector_decimator import stream_to_vector_decimator +import math + +class _logpwrfft_base(gr.hier_block2): + """ + Create a log10(abs(fft)) stream chain, with real or complex input. + """ + + def __init__(self, sample_rate, fft_size, ref_scale, frame_rate, avg_alpha, average, win=None): + """ + Create an log10(abs(fft)) stream chain. + Provide access to the setting the filter and sample rate. + @param sample_rate Incoming stream sample rate + @param fft_size Number of FFT bins + @param ref_scale Sets 0 dB value input amplitude + @param frame_rate Output frame rate + @param avg_alpha FFT averaging (over time) constant [0.0-1.0] + @param average Whether to average [True, False] + @param win the window taps generation function + """ + gr.hier_block2.__init__(self, self._name, + gr.io_signature(1, 1, self._item_size), # Input signature + gr.io_signature(1, 1, gr.sizeof_float*fft_size)) # Output signature + + self._sd = stream_to_vector_decimator(item_size=self._item_size, + sample_rate=sample_rate, + vec_rate=frame_rate, + vec_len=fft_size) + + if win is None: win = window.blackmanharris + fft_window = win(fft_size) + fft = self._fft_block[0](fft_size, True, fft_window) + window_power = sum(map(lambda x: x*x, fft_window)) + + c2magsq = gr.complex_to_mag_squared(fft_size) + self._avg = gr.single_pole_iir_filter_ff(1.0, fft_size) + self._log = gr.nlog10_ff(10, fft_size, + -20*math.log10(fft_size) # Adjust for number of bins + -10*math.log10(window_power/fft_size) # Adjust for windowing loss + -20*math.log10(ref_scale/2)) # Adjust for reference scale + self.connect(self, self._sd, fft, c2magsq, self._avg, self._log, self) + + self._average = average + self._avg_alpha = avg_alpha + self.set_avg_alpha(avg_alpha) + self.set_average(average) + + def set_decimation(self, decim): + """ + Set the decimation on stream decimator. + @param decim the new decimation + """ + self._sd.set_decimation(decim) + + def set_vec_rate(self, vec_rate): + """ + Set the vector rate on stream decimator. + @param vec_rate the new vector rate + """ + self._sd.set_vec_rate(vec_rate) + + def set_sample_rate(self, sample_rate): + """ + Set the new sampling rate + @param sample_rate the new rate + """ + self._sd.set_sample_rate(sample_rate) + + def set_average(self, average): + """ + Set the averaging filter on/off. + @param average true to set averaging on + """ + self._average = average + if self._average: + self._avg.set_taps(self._avg_alpha) + else: + self._avg.set_taps(1.0) + + def set_avg_alpha(self, avg_alpha): + """ + Set the average alpha and set the taps if average was on. + @param avg_alpha the new iir filter tap + """ + self._avg_alpha = avg_alpha + self.set_average(self._average) + + def sample_rate(self): + """ + Return the current sample rate. + """ + return self._sd.sample_rate() + + def decimation(self): + """ + Return the current decimation. + """ + return self._sd.decimation() + + def frame_rate(self): + """ + Return the current frame rate. + """ + return self._sd.frame_rate() + + def average(self): + """ + Return whether or not averaging is being performed. + """ + return self._average + + def avg_alpha(self): + """ + Return averaging filter constant. + """ + return self._avg_alpha + +class logpwrfft_f(_logpwrfft_base): + """ + Create an fft block chain, with real input. + """ + _name = "logpwrfft_f" + _item_size = gr.sizeof_float + _fft_block = (gr.fft_vfc, ) + +class logpwrfft_c(_logpwrfft_base): + """ + Create an fft block chain, with complex input. + """ + _name = "logpwrfft_c" + _item_size = gr.sizeof_gr_complex + _fft_block = (gr.fft_vcc, ) + |