Typo fix. Added 44.1 kHz as possible sampling frequency for computing filters.
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@ -67,7 +67,7 @@ std::vector<unique_ptr<Filter>> createBandPass(const dmat &coefs) {
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return bf;
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}
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us SLM::suggestedDownSamplingFac(const d fs,const d tau) {
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if(tau<0) throw rte("Invalid time weightin time constant");
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if(tau<0) throw rte("Invalid time weighting time constant");
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if(fs<=0) throw rte("Invalid sampling frequency");
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// A reasonable 'framerate' for the sound level meter, based on the
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// filtering time constant.
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@ -10,12 +10,14 @@ Resulting filters are supposed to be standard compliant.
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See test/octave_fir_test.py for a testing
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"""
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from .fir_design import bandpass_fir_design, freqResponse as firFreqResponse
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import numpy as np
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import warnings
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import numpy as np
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# For designing second-order sections
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from scipy.signal import butter
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from .fir_design import bandpass_fir_design
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from .fir_design import freqResponse as firFreqResponse
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__all__ = ['OctaveBankDesigner', 'ThirdOctaveBankDesigner']
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@ -61,11 +63,13 @@ class FilterBankDesigner:
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# Interpolate limites to frequency array as given
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llim_full = np.interp(freq, freqlim, llim, left=-np.inf, right=-np.inf)
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ulim_full = np.interp(freq, freqlim, ulim,
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left=ulim[0], right=ulim[-1])
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ulim_full = np.interp(freq,
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freqlim,
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ulim,
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left=ulim[0],
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right=ulim[-1])
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return bool(np.all(llim_full <= h_dB) and
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np.all(ulim_full >= h_dB))
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return bool(np.all(llim_full <= h_dB) and np.all(ulim_full >= h_dB))
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def band_limits(self, x, filter_class):
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raise NotImplementedError()
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@ -81,7 +85,8 @@ class FilterBankDesigner:
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if self.nominal_txt(x) == nom_txt:
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return x
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raise ValueError(
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f'Could not find a nominal frequency corresponding to {nom_txt}. Hint: use \'5k\' instead of \'5000\'.')
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f'Could not find a nominal frequency corresponding to {nom_txt}. Hint: use \'5k\' instead of \'5000\'.'
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)
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def sanitize_input(self, input_):
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if isinstance(input_, int):
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@ -99,7 +104,6 @@ class FilterBankDesigner:
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x = [self.sanitize_input(xi) for xi in input_]
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return np.asarray(x)
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def getxs(self, nom_txt_start, nom_txt_end):
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"""Returns a list of all filter designators, for given start end end
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nominal frequencies.
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@ -114,6 +118,7 @@ class FilterBankDesigner:
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xstart = self.nominal_txt_tox(nom_txt_start)
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xend = self.nominal_txt_tox(nom_txt_end)
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return list(range(xstart, xend + 1))
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def fm(self, x):
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"""Returns the exact midband frequency of the bandpass filter.
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@ -200,9 +205,11 @@ class FilterBankDesigner:
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return firFreqResponse(fd, freq, fir)
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def getNarrowBandFromOctaveBand(self, xl, xu,
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levels_in_bands, npoints=500,
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def getNarrowBandFromOctaveBand(self,
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xl,
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xu,
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levels_in_bands,
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npoints=500,
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method='flat',
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scale='lin'):
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"""Create a narrow band spectrum based on a spectrum in (fractional)
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@ -351,11 +358,11 @@ class OctaveBankDesigner(FilterBankDesigner):
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mininf = -1e300
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if filter_class == 1:
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lower_limits_pos = [-0.3, -0.4, -
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0.6, -1.3, -5.0, -5.0] + 4*[mininf]
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lower_limits_pos = [-0.3, -0.4, -0.6, -1.3, -5.0, -5.0
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] + 4 * [mininf]
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elif filter_class == 0:
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lower_limits_pos = [-0.15, -0.2, -
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0.4, -1.1, -4.5, -4.5] + 4*[mininf]
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lower_limits_pos = [-0.15, -0.2, -0.4, -1.1, -4.5, -4.5
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] + 4 * [mininf]
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lower_limits_neg = lower_limits_pos[:]
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lower_limits_neg.reverse()
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lower_limits = np.asarray(lower_limits_neg[:-1] + lower_limits_pos)
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@ -375,7 +382,8 @@ class OctaveBankDesigner(FilterBankDesigner):
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def nominal_txt(self, x):
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"""Returns textual repressentation of corresponding to the nominal
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frequency."""
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nominals = {4: '16k',
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nominals = {
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4: '16k',
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3: '8k',
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2: '4k',
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1: '2k',
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@ -385,7 +393,8 @@ class OctaveBankDesigner(FilterBankDesigner):
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-3: '125',
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-4: '63',
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-5: '31.5',
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-6: '16'}
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-6: '16'
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}
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assert len(nominals) == len(self.xs)
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return nominals[x]
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@ -472,16 +481,12 @@ class ThirdOctaveBankDesigner(FilterBankDesigner):
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super().__init__(fs)
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self.xs = list(range(-16, 14))
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# Text corresponding to the nominal frequency
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self._nominal_txt = ['25', '31.5', '40',
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'50', '63', '80',
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'100', '125', '160',
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'200', '250', '315',
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'400', '500', '630',
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'800', '1k', '1.25k',
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'1.6k', '2k', '2.5k',
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'3.15k', '4k', '5k',
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'6.3k', '8k', '10k',
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'12.5k', '16k', '20k']
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self._nominal_txt = [
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'25', '31.5', '40', '50', '63', '80', '100', '125', '160', '200',
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'250', '315', '400', '500', '630', '800', '1k', '1.25k', '1.6k',
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'2k', '2.5k', '3.15k', '4k', '5k', '6.3k', '8k', '10k', '12.5k',
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'16k', '20k'
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]
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assert len(self.xs) == len(self._nominal_txt)
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@ -501,7 +506,6 @@ class ThirdOctaveBankDesigner(FilterBankDesigner):
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index_stop = x[-1] - self.xs[0]
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return self._nominal_txt[index_start:index_stop + 1]
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def band_limits(self, x, filter_class=0):
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"""Returns the third octave band filter limits for filter designator x.
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@ -518,11 +522,15 @@ class ThirdOctaveBankDesigner(FilterBankDesigner):
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fm = self.G**(x / self.b) * self.fr
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plusinf = 20
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f_ratio_pos = [1., 1.02667, 1.05575, 1.08746, 1.12202, 1.12202,
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1.29437, 1.88173, 3.05365, 5.39195, plusinf]
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f_ratio_pos = [
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1., 1.02667, 1.05575, 1.08746, 1.12202, 1.12202, 1.29437, 1.88173,
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3.05365, 5.39195, plusinf
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]
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f_ratio_neg = [0.97402, 0.94719, 0.91958, 0.89125, 0.89125,
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0.77257, 0.53143, 0.32748, 0.18546, 1/plusinf]
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f_ratio_neg = [
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0.97402, 0.94719, 0.91958, 0.89125, 0.89125, 0.77257, 0.53143,
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0.32748, 0.18546, 1 / plusinf
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]
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f_ratio_neg.reverse()
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f_ratio = f_ratio_neg + f_ratio_pos
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@ -541,11 +549,15 @@ class ThirdOctaveBankDesigner(FilterBankDesigner):
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upper_limits = np.array(upper_limits_neg[:-1] + upper_limits_pos)
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if filter_class == 1:
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lower_limits_pos = [-.3, -.4, -.6, -1.3, -5, -5, mininf, mininf,
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mininf, mininf, mininf]
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lower_limits_pos = [
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-.3, -.4, -.6, -1.3, -5, -5, mininf, mininf, mininf, mininf,
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mininf
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]
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elif filter_class == 0:
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lower_limits_pos = [-.15, -.2, -.4, -1.1, -4.5, -4.5, mininf, mininf,
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mininf, mininf, mininf]
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lower_limits_pos = [
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-.15, -.2, -.4, -1.1, -4.5, -4.5, mininf, mininf, mininf,
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mininf, mininf
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]
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lower_limits_neg = lower_limits_pos[:]
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lower_limits_neg.reverse()
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@ -592,13 +604,17 @@ class ThirdOctaveBankDesigner(FilterBankDesigner):
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filter."""
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# Idea: correct for frequency warping:
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if np.isclose(self.fs, 48000):
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return 1.00
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elif np.isclose(self.fs, 41000):
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warnings.warn(
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f'Frequency {self.fs} might not result in correct filters')
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return 1.00
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elif np.isclose(self.fs, 32768):
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return 1.00
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else:
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raise ValueError('Unimplemented sampling frequency for SOS'
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'filter design')
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def sosFac_u(self, x):
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"""Right side percentage of change in cut-on frequency for designing
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the filter."""
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