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# Copyright 2008 Free Software Foundation, Inc.
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# This file is part of GNU Radio
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# GNU Radio is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3, or (at your option)
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# GNU Radio is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with GNU Radio; see the file COPYING. If not, write to
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# the Free Software Foundation, Inc., 51 Franklin Street,
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# Boston, MA 02110-1301, USA.
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from gnuradio import gr, window
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from stream_to_vector_decimator import stream_to_vector_decimator
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class _logpwrfft_base(gr.hier_block2):
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Create a log10(abs(fft)) stream chain, with real or complex input.
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def __init__(self, sample_rate, fft_size, ref_scale, frame_rate, avg_alpha, average):
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Create an log10(abs(fft)) stream chain.
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Provide access to the setting the filter and sample rate.
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@param sample_rate Incoming stream sample rate
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@param fft_size Number of FFT bins
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@param ref_scale Sets 0 dB value input amplitude
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@param frame_rate Output frame rate
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@param avg_alpha FFT averaging (over time) constant [0.0-1.0]
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@param average Whether to average [True, False]
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gr.hier_block2.__init__(self, self._name,
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gr.io_signature(1, 1, self._item_size), # Input signature
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gr.io_signature(1, 1, gr.sizeof_float*fft_size)) # Output signature
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self._sd = stream_to_vector_decimator(item_size=self._item_size,
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sample_rate=sample_rate,
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fft_window = window.blackmanharris(fft_size)
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fft = self._fft_block[0](fft_size, True, fft_window)
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window_power = sum(map(lambda x: x*x, fft_window))
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c2mag = gr.complex_to_mag(fft_size)
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self._avg = gr.single_pole_iir_filter_ff(1.0, fft_size)
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self._log = gr.nlog10_ff(20, fft_size,
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-10*math.log10(fft_size) # Adjust for number of bins
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-10*math.log10(window_power/fft_size) # Adjust for windowing loss
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-20*math.log10(ref_scale/2)) # Adjust for reference scale
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self.connect(self, self._sd, fft, c2mag, self._avg, self._log, self)
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self._average = average
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self._avg_alpha = avg_alpha
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self.set_avg_alpha(avg_alpha)
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self.set_average(average)
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def set_decimation(self, decim):
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Set the decimation on stream decimator.
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@param decim the new decimation
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self._sd.set_decimation(decim)
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def set_vec_rate(self, vec_rate):
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Set the vector rate on stream decimator.
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@param vec_rate the new vector rate
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self._sd.set_vec_rate(vec_rate)
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def set_sample_rate(self, sample_rate):
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Set the new sampling rate
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@param sample_rate the new rate
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self._sd.set_sample_rate(sample_rate)
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def set_average(self, average):
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Set the averaging filter on/off.
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@param average true to set averaging on
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self._average = average
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self._avg.set_taps(self._avg_alpha)
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self._avg.set_taps(1.0)
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def set_avg_alpha(self, avg_alpha):
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Set the average alpha and set the taps if average was on.
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@param avg_alpha the new iir filter tap
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self._avg_alpha = avg_alpha
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self.set_average(self._average)
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def sample_rate(self):
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Return the current sample rate.
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return self._sd.sample_rate()
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def decimation(self):
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Return the current decimation.
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return self._sd.decimation()
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def frame_rate(self):
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Return the current frame rate.
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return self._sd.frame_rate()
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Return whether or not averaging is being performed.
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Return averaging filter constant.
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return self._avg_alpha
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class logpwrfft_f(_logpwrfft_base):
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Create an fft block chain, with real input.
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_name = "logpwrfft_f"
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_item_size = gr.sizeof_float
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_fft_block = (gr.fft_vfc, )
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class logpwrfft_c(_logpwrfft_base):
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Create an fft block chain, with complex input.
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_name = "logpwrfft_c"
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_item_size = gr.sizeof_gr_complex
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_fft_block = (gr.fft_vcc, )