Major cleanup and improvements of filter design code.
This commit is contained in:
parent
54173b6ecc
commit
00bd30eb2a
@ -1,5 +1,4 @@
|
||||
from .soundpressureweighting import *
|
||||
from .filterbank_design import OctaveBankDesigner, ThirdOctaveBankDesigner
|
||||
from .filterbank_standard_limits import octave_band_limits, third_octave_band_limits
|
||||
from .filterbank_design import *
|
||||
from .fir_design import *
|
||||
|
||||
|
||||
@ -4,28 +4,71 @@
|
||||
Author: J.A. de Jong - ASCEE
|
||||
|
||||
Description: FIR filter design for octave bands from 16Hz to 16 kHz for a
|
||||
sampling frequency of 48 kHz, FIR filter design for one-third octave bands
|
||||
sampling frequency of 48 kHz, filter design for one-third octave bands.
|
||||
Resulting filters are supposed to be standard compliant.
|
||||
|
||||
See test/octave_fir_test.py for a testing
|
||||
|
||||
"""
|
||||
from .fir_design import bandpass_fir_design, freqResponse as frsp
|
||||
from .fir_design import bandpass_fir_design, freqResponse as firFreqResponse
|
||||
import numpy as np
|
||||
|
||||
# For designing second-order sections
|
||||
from scipy.signal import butter
|
||||
|
||||
|
||||
__all__ = ['OctaveBankDesigner', 'ThirdOctaveBankDesigner']
|
||||
|
||||
|
||||
class FilterBankDesigner:
|
||||
"""
|
||||
A class responsible for designing FIR filters
|
||||
"""
|
||||
G = 10**(3/10)
|
||||
fr = 1000.
|
||||
L = 256 # Filter order
|
||||
fs = 48000. # Sampling frequency
|
||||
"""A class responsible for designing FIR filters."""
|
||||
|
||||
def __init__(self, fs):
|
||||
"""Initialize a filter bank designer.
|
||||
|
||||
Args:
|
||||
fs: Sampling frequency [Hz]
|
||||
"""
|
||||
# Default FIR filter length
|
||||
firFilterLength = 256 # Filter order
|
||||
self.fs = fs
|
||||
|
||||
# Constant G, according to standard
|
||||
self.G = 10**(3/10)
|
||||
|
||||
# Reference frequency for all filter banks
|
||||
self.fr = 1000.
|
||||
|
||||
def testStandardCompliance(self, x, freq, h_dB, filter_class=0):
|
||||
"""Test whether the filter with given frequency response is compliant
|
||||
with the standard.
|
||||
|
||||
Args:
|
||||
x: Band designator
|
||||
freq: Array of frequencies to test for. Note: *Should be fine
|
||||
enough to follow response!*
|
||||
h_dB: Filter frequency response in *deciBell*
|
||||
filter_class: Filter class to test for
|
||||
|
||||
Returns:
|
||||
True if filter is norm-compliant, False if not
|
||||
|
||||
"""
|
||||
# Skip zero-frequency
|
||||
if np.isclose(freq[0], 0):
|
||||
freq = freq[1:]
|
||||
h_dB = h_dB[1:]
|
||||
freqlim, llim, ulim = self.band_limits(x, filter_class)
|
||||
|
||||
# Interpolate limites to frequency array as given
|
||||
llim_full = np.interp(freq, freqlim, llim, left=-np.inf, right=-np.inf)
|
||||
ulim_full = np.interp(freq, freqlim, ulim, left=ulim[0], right=ulim[-1])
|
||||
|
||||
return bool(np.all(llim_full <= h_dB) and
|
||||
np.all(ulim_full >= h_dB))
|
||||
|
||||
def fm(self, x):
|
||||
"""
|
||||
Returns the exact midband frequency of the bandpass filter
|
||||
"""Returns the exact midband frequency of the bandpass filter.
|
||||
|
||||
Args:
|
||||
x: Midband designator
|
||||
@ -34,8 +77,7 @@ class FilterBankDesigner:
|
||||
return self.G**(x/self.b)*self.fr
|
||||
|
||||
def fl(self, x):
|
||||
"""
|
||||
Returns the exact cut-on frequency of the bandpass filter
|
||||
"""Returns the exact cut-on frequency of the bandpass filter.
|
||||
|
||||
Args:
|
||||
x: Midband designator
|
||||
@ -43,50 +85,75 @@ class FilterBankDesigner:
|
||||
return self.fm(x)*self.G**(-1/(2*self.b))
|
||||
|
||||
def fu(self, x):
|
||||
"""
|
||||
Returns the exact cut-off frequency of the bandpass filter
|
||||
"""Returns the exact cut-off frequency of the bandpass filter.
|
||||
|
||||
Args:
|
||||
x: Midband designator
|
||||
"""
|
||||
return self.fm(x)*self.G**(1/(2*self.b))
|
||||
|
||||
def createFirFilter(self, fs, x):
|
||||
"""
|
||||
Create a FIR filter for band designator b and sampling frequency fs.
|
||||
Decimation should be obtained from decimation() method.
|
||||
def createFirFilter(self, x):
|
||||
"""Create a FIR filter for band designator b and sampling frequency fs.
|
||||
firdecimation should be obtained from firdecimation() method.
|
||||
|
||||
Returns:
|
||||
filter: 1D ndarray with FIR filter coefficients
|
||||
"""
|
||||
assert np.isclose(fs, self.fs), "Invalid sampling frequency"
|
||||
fd = fs / np.prod(self.decimation(x))
|
||||
fd = fs / np.prod(self.firDecimation(x))
|
||||
|
||||
# For designing the filter, the lower and upper frequencies need to be
|
||||
# slightly adjusted to fall within the limits for a class 1 filter.
|
||||
fl = self.fl(x)*self.fac_l(x)
|
||||
fu = self.fu(x)*self.fac_u(x)
|
||||
fl = self.fl(x)*self.firFac_l(x)
|
||||
fu = self.fu(x)*self.firFac_u(x)
|
||||
|
||||
return bandpass_fir_design(self.L, fd, fl, fu)
|
||||
return bandpass_fir_design(self.firFilterLength, fd, fl, fu)
|
||||
|
||||
def freqResponse(self, fs, x, freq):
|
||||
"""
|
||||
Compute the frequency response for a certain filter
|
||||
def createSOSFilter(self, x: int):
|
||||
"""Create a Second Order Section filter (cascaded BiQuad's) for the
|
||||
given sample rate and band designator.
|
||||
|
||||
Args:
|
||||
fs: Sampling frequency [Hz]
|
||||
x: Midband designator
|
||||
x: Band designator
|
||||
"""
|
||||
fir = self.createFilter(fs, x)
|
||||
|
||||
SOS_ORDER = 5
|
||||
|
||||
fs = self.fs
|
||||
fl = self.fl(x)*self.sosFac_l(x)
|
||||
fu = self.fu(x)*self.sosFac_u(x)
|
||||
|
||||
fnyq = fs/2
|
||||
|
||||
# Normalized upper and lower frequencies of the bandpass
|
||||
fl_n = fl/fnyq
|
||||
fu_n = fu/fnyq
|
||||
|
||||
return butter(SOS_ORDER, [fl_n, fu_n], output='sos', btype='band')
|
||||
|
||||
def firFreqResponse(self, x, freq):
|
||||
"""Compute the frequency response for a certain filter.
|
||||
|
||||
Args:
|
||||
x: Midband designator
|
||||
freq: Array of frequencies to evaluate on
|
||||
|
||||
Returns:
|
||||
h: Linear filter transfer function [-]
|
||||
"""
|
||||
fir = self.createFirFilter(fs, x)
|
||||
|
||||
# Decimated sampling frequency [Hz]
|
||||
fd = fs / np.prod(self.decimation(x))
|
||||
fd = fs / np.prod(self.firdecimation(x))
|
||||
|
||||
return frsp(fd, freq, fir)
|
||||
return firFreqResponse(fd, freq, fir)
|
||||
|
||||
def nominal_txt_tox(self, nom_txt):
|
||||
"""
|
||||
Returns the x-value corresponding to a certain nominal txt: '1k' -> 0
|
||||
def nominal_txt_tox(self, nom_txt: str):
|
||||
"""Returns the x-value corresponding to a certain nominal txt: '1k' ->
|
||||
0.
|
||||
|
||||
Args:
|
||||
nom_txt: Text-representation of midband frequency
|
||||
"""
|
||||
for x in self.xs:
|
||||
if self.nominal_txt(x) == nom_txt:
|
||||
@ -96,12 +163,10 @@ class FilterBankDesigner:
|
||||
|
||||
|
||||
class OctaveBankDesigner(FilterBankDesigner):
|
||||
"""
|
||||
Octave band filter designer
|
||||
"""
|
||||
"""Octave band filter designer."""
|
||||
|
||||
def __init__(self):
|
||||
pass
|
||||
def __init__(self, fs):
|
||||
super().__init__(fs)
|
||||
|
||||
@property
|
||||
def b(self):
|
||||
@ -110,10 +175,58 @@ class OctaveBankDesigner(FilterBankDesigner):
|
||||
|
||||
@property
|
||||
def xs(self):
|
||||
"""All possible band designators for an octave band filter."""
|
||||
return list(range(-6, 5))
|
||||
|
||||
def band_limits(self, x, filter_class=0):
|
||||
"""Returns the octave band filter limits for filter designator x.
|
||||
|
||||
Args:
|
||||
x: Filter offset power from the reference frequency of 1000 Hz.
|
||||
filter_class: Either 0 or 1, defines the tolerances on the frequency
|
||||
response
|
||||
|
||||
Returns:
|
||||
freq, llim, ulim: Tuple of Numpy arrays containing the frequencies of
|
||||
the corner points of the filter frequency response limits, lower limits
|
||||
in *deciBell*, upper limits in *deciBell*, respectively.
|
||||
"""
|
||||
b = 1
|
||||
|
||||
# Exact midband frequency
|
||||
fm = self.G**(x/self.b)*self.fr
|
||||
|
||||
G_power_values_pos = [0, 1/8, 1/4, 3/8, 1/2, 1/2, 1, 2, 3, 4]
|
||||
G_power_values_neg = [-i for i in G_power_values_pos]
|
||||
G_power_values_neg.reverse()
|
||||
G_power_values = G_power_values_neg[:-1] + G_power_values_pos
|
||||
|
||||
mininf = -1e300
|
||||
|
||||
if filter_class == 1:
|
||||
lower_limits_pos = [-0.3, -0.4, -0.6, -1.3, -5.0, -5.0] + 4*[mininf]
|
||||
elif filter_class == 0:
|
||||
lower_limits_pos = [-0.15, -0.2, -0.4, -1.1, -4.5, -4.5] + 4*[mininf]
|
||||
lower_limits_neg = lower_limits_pos[:]
|
||||
lower_limits_neg.reverse()
|
||||
lower_limits = np.asarray(lower_limits_neg[:-1] + lower_limits_pos)
|
||||
|
||||
if filter_class == 1:
|
||||
upper_limits_pos = [0.3]*5 + [-2, -17.5, -42, -61, -70]
|
||||
if filter_class == 0:
|
||||
upper_limits_pos = [0.15]*5 + [-2.3, -18, -42.5, -62, -75]
|
||||
upper_limits_neg = upper_limits_pos[:]
|
||||
upper_limits_neg.reverse()
|
||||
upper_limits = np.asarray(upper_limits_neg[:-1] + upper_limits_pos)
|
||||
|
||||
freqs = fm*self.G**np.asarray(G_power_values)
|
||||
|
||||
return freqs, lower_limits, upper_limits
|
||||
|
||||
|
||||
def nominal_txt(self, x):
|
||||
# Text corresponding to the nominal frequency
|
||||
"""Returns textual repressentation of corresponding to the nominal
|
||||
frequency."""
|
||||
nominals = {4: '16k',
|
||||
3: '8k',
|
||||
2: '4k',
|
||||
@ -125,12 +238,13 @@ class OctaveBankDesigner(FilterBankDesigner):
|
||||
-4: '63',
|
||||
-5: '31.5',
|
||||
-6: '16'}
|
||||
assert len(nominals) == len(self.xs)
|
||||
return nominals[x]
|
||||
|
||||
def fac_l(self, x):
|
||||
"""
|
||||
Factor with which to multiply the cut-on frequency of the FIR filter
|
||||
"""
|
||||
def firFac_l(self, x):
|
||||
"""Factor with which to multiply the cut-on frequency of the FIR
|
||||
filter."""
|
||||
assert int(self.fs) == 48000, 'Fir coefs are only valid for 48kHz fs'
|
||||
if x == 4:
|
||||
return .995
|
||||
elif x in (3, 1):
|
||||
@ -140,10 +254,10 @@ class OctaveBankDesigner(FilterBankDesigner):
|
||||
else:
|
||||
return .96
|
||||
|
||||
def fac_u(self, x):
|
||||
"""
|
||||
Factor with which to multiply the cut-off frequency of the FIR filter
|
||||
"""
|
||||
def firFac_u(self, x):
|
||||
"""Factor with which to multiply the cut-off frequency of the FIR
|
||||
filter."""
|
||||
assert int(self.fs) == 48000, 'Fir coefs are only valid for 48kHz fs'
|
||||
if x == 4:
|
||||
return 1.004
|
||||
elif x in (3, 1):
|
||||
@ -153,10 +267,9 @@ class OctaveBankDesigner(FilterBankDesigner):
|
||||
else:
|
||||
return 1.02
|
||||
|
||||
def decimation(self, x):
|
||||
"""
|
||||
Required decimation for each filter
|
||||
"""
|
||||
def firDecimation(self, x):
|
||||
"""Required firdecimation for each filter."""
|
||||
assert int(self.fs) == 48000, 'Fir coefs are only valid for 48kHz fs'
|
||||
if x > 1:
|
||||
return [1]
|
||||
elif x > -2:
|
||||
@ -167,24 +280,52 @@ class OctaveBankDesigner(FilterBankDesigner):
|
||||
return [4, 4, 4]
|
||||
elif x == -6:
|
||||
return [4, 4, 4, 4]
|
||||
assert False, 'Overlooked decimation'
|
||||
assert False, 'Overlooked firdecimation'
|
||||
|
||||
def sosFac_l(self, x):
|
||||
"""Left side percentage of change in cut-on frequency for designing the
|
||||
filter, for OCTAVE band filter.
|
||||
|
||||
Args:
|
||||
x: Filter band designator
|
||||
"""
|
||||
# Idea: correct for frequency warping:
|
||||
if int(self.fs) in [48000, 96000]:
|
||||
return 1.0
|
||||
else:
|
||||
raise ValueError('Unimplemented sampling frequency for SOS'
|
||||
'filter design')
|
||||
|
||||
def sosFac_u(self, x):
|
||||
"""Right side percentage of change in cut-on frequency for designing
|
||||
the filter.
|
||||
|
||||
Args:
|
||||
x: Filter band designator
|
||||
"""
|
||||
if int(self.fs) in [48000, 96000]:
|
||||
return 1.0
|
||||
else:
|
||||
raise ValueError('Unimplemented sampling frequency for SOS'
|
||||
'filter design')
|
||||
|
||||
|
||||
class ThirdOctaveBankDesigner(FilterBankDesigner):
|
||||
|
||||
def __init__(self):
|
||||
def __init__(self, fs):
|
||||
super().__init__(fs)
|
||||
self.xs = list(range(-16, 14))
|
||||
# Text corresponding to the nominal frequency
|
||||
self._nominal_txt = ['25', '31.5', '40',
|
||||
'50', '63', '80',
|
||||
'100', '125', '160',
|
||||
'200', '250', '315',
|
||||
'400', '500', '630',
|
||||
'800', '1k', '1.25k',
|
||||
'1.6k', '2k', '2.5k',
|
||||
'3.15k', '4k', '5k',
|
||||
'6.3k', '8k', '10k',
|
||||
'12.5k', '16k', '20k']
|
||||
'50', '63', '80',
|
||||
'100', '125', '160',
|
||||
'200', '250', '315',
|
||||
'400', '500', '630',
|
||||
'800', '1k', '1.25k',
|
||||
'1.6k', '2k', '2.5k',
|
||||
'3.15k', '4k', '5k',
|
||||
'6.3k', '8k', '10k',
|
||||
'12.5k', '16k', '20k']
|
||||
|
||||
assert len(self.xs) == len(self._nominal_txt)
|
||||
|
||||
@ -199,8 +340,61 @@ class ThirdOctaveBankDesigner(FilterBankDesigner):
|
||||
index = x - self.xs[0]
|
||||
return self._nominal_txt[index]
|
||||
|
||||
@staticmethod
|
||||
def decimation(x):
|
||||
def band_limits(self, x, filter_class=0):
|
||||
"""Returns the third octave band filter limits for filter designator x.
|
||||
|
||||
Args:
|
||||
x: Filter offset power from the reference frequency of 1000 Hz.
|
||||
filter_class: Either 0 or 1, defines the tolerances on the frequency
|
||||
response
|
||||
|
||||
Returns:
|
||||
freq, llim, ulim: Tuple of Numpy arrays containing the frequencies of
|
||||
the corner points of the filter frequency response limits, lower limits
|
||||
in *deciBell*, upper limits in *deciBell*, respectively.
|
||||
"""
|
||||
|
||||
fm = self.G**(x/self.b)*self.fr
|
||||
plusinf = 20
|
||||
f_ratio_pos = [1., 1.02667, 1.05575, 1.08746, 1.12202, 1.12202,
|
||||
1.29437, 1.88173, 3.05365, 5.39195, plusinf]
|
||||
|
||||
f_ratio_neg = [0.97402, 0.94719, 0.91958, 0.89125, 0.89125,
|
||||
0.77257, 0.53143, 0.32748, 0.18546, 1/plusinf]
|
||||
f_ratio_neg.reverse()
|
||||
|
||||
f_ratio = f_ratio_neg + f_ratio_pos
|
||||
|
||||
mininf = -1e300
|
||||
|
||||
if filter_class == 1:
|
||||
upper_limits_pos = [.3]*5 + [-2, -17.5, -42, -61, -70, -70]
|
||||
elif filter_class == 0:
|
||||
upper_limits_pos = [.15]*5 + [-2.3, -18, -42.5, -62, -75, -75]
|
||||
else:
|
||||
raise ValueError('Filter class should either be 0 or 1')
|
||||
|
||||
upper_limits_neg = upper_limits_pos[:]
|
||||
upper_limits_neg.reverse()
|
||||
upper_limits = np.array(upper_limits_neg[:-1] + upper_limits_pos)
|
||||
|
||||
if filter_class == 1:
|
||||
lower_limits_pos = [-.3, -.4, -.6, -1.3, -5, -5, mininf, mininf,
|
||||
mininf, mininf, mininf]
|
||||
elif filter_class == 0:
|
||||
lower_limits_pos = [-.15, -.2, -.4, -1.1, -4.5, -4.5, mininf, mininf,
|
||||
mininf, mininf, mininf]
|
||||
|
||||
lower_limits_neg = lower_limits_pos[:]
|
||||
lower_limits_neg.reverse()
|
||||
lower_limits = np.array(lower_limits_neg[:-1] + lower_limits_pos)
|
||||
|
||||
freqs = fm*np.array(f_ratio)
|
||||
|
||||
return freqs, lower_limits, upper_limits
|
||||
|
||||
def firDecimation(self, x):
|
||||
assert int(self.fs) == 48000, 'Fir coefs are only valid for 48kHz fs'
|
||||
if x > 5:
|
||||
return [1]
|
||||
elif x > -1:
|
||||
@ -211,10 +405,9 @@ class ThirdOctaveBankDesigner(FilterBankDesigner):
|
||||
return [4, 4, 4]
|
||||
elif x > -17:
|
||||
return [4, 4, 4, 4]
|
||||
assert False, 'Bug: overlooked decimation'
|
||||
assert False, 'Bug: overlooked firdecimation'
|
||||
|
||||
@staticmethod
|
||||
def fac_l(x):
|
||||
def firFac_l(self, x):
|
||||
if x in (-13, -7, -1, 5, 11, 12, 13):
|
||||
return .995
|
||||
elif x in (-12, -6, 0, 6):
|
||||
@ -222,8 +415,7 @@ class ThirdOctaveBankDesigner(FilterBankDesigner):
|
||||
else:
|
||||
return .99
|
||||
|
||||
@staticmethod
|
||||
def fac_u(x):
|
||||
def firFac_u(self, x):
|
||||
if x in (-14, -13, -8, -7, -1, -2, 3, 4, 5, 10, 11, 12):
|
||||
return 1.005
|
||||
elif x in (12, 13):
|
||||
@ -232,3 +424,22 @@ class ThirdOctaveBankDesigner(FilterBankDesigner):
|
||||
return 1.015
|
||||
else:
|
||||
return 1.01
|
||||
|
||||
def sosFac_l(self, x):
|
||||
"""Left side percentage of change in cut-on frequency for designing the
|
||||
filter."""
|
||||
# Idea: correct for frequency warping:
|
||||
if np.isclose(self.fs, 48000):
|
||||
return 1.00
|
||||
else:
|
||||
raise ValueError('Unimplemented sampling frequency for SOS'
|
||||
'filter design')
|
||||
|
||||
def sosFac_u(self, x):
|
||||
"""Right side percentage of change in cut-on frequency for designing
|
||||
the filter."""
|
||||
if np.isclose(self.fs, 48000):
|
||||
return 1
|
||||
else:
|
||||
raise ValueError('Unimplemented sampling frequency for SOS'
|
||||
'filter design')
|
||||
|
||||
@ -1,99 +0,0 @@
|
||||
#!/usr/bin/env python3
|
||||
# -*- coding: utf-8 -*-
|
||||
"""!
|
||||
Author: J.A. de Jong - ASCEE
|
||||
|
||||
Description: Limit lines for class 1 octave band filter limits according to
|
||||
the ICS 17.140.50 standard.
|
||||
"""
|
||||
__all__ = ['G', 'fr', 'third_octave_band_limits', 'octave_band_limits']
|
||||
import numpy as np
|
||||
|
||||
# Reference frequency
|
||||
fr = 1000.
|
||||
G = 10**(3/10)
|
||||
|
||||
|
||||
def third_octave_band_limits(x):
|
||||
"""
|
||||
Returns the class 1 third octave band filter limits for filter designator
|
||||
x.
|
||||
|
||||
Args:
|
||||
x: Filter offset power from the reference frequency of 1000 Hz.
|
||||
|
||||
Returns:
|
||||
freq, ulim, llim: Tuple of Numpy arrays containing the frequencyies,
|
||||
upper and lower limits of the filter.
|
||||
"""
|
||||
b = 3
|
||||
|
||||
fm = G**(x/b)*fr
|
||||
plusinf = 20
|
||||
f_ratio_pos = [1., 1.02667, 1.05575, 1.08746, 1.12202, 1.12202,
|
||||
1.29437, 1.88173, 3.05365, 5.39195, plusinf]
|
||||
|
||||
f_ratio_neg = [0.97402, 0.94719, 0.91958, 0.89125, 0.89125,
|
||||
0.77257, 0.53143, 0.32748, 0.18546, 1/plusinf]
|
||||
f_ratio_neg.reverse()
|
||||
|
||||
f_ratio = f_ratio_neg + f_ratio_pos
|
||||
|
||||
mininf = -1e300
|
||||
|
||||
upper_limits_pos = [.3]*5 + [-2, -17.5, -42, -61, -70, -70]
|
||||
upper_limits_neg = upper_limits_pos[:]
|
||||
upper_limits_neg.reverse()
|
||||
upper_limits = np.array(upper_limits_neg[:-1] + upper_limits_pos)
|
||||
|
||||
lower_limits_pos = [-.3, -.4, -.6, -1.3, -5, -5, mininf, mininf,
|
||||
mininf, mininf, mininf]
|
||||
lower_limits_neg = lower_limits_pos[:]
|
||||
lower_limits_neg.reverse()
|
||||
lower_limits = np.array(lower_limits_neg[:-1] + lower_limits_pos)
|
||||
|
||||
freqs = fm*np.array(f_ratio)
|
||||
|
||||
return freqs, upper_limits, lower_limits
|
||||
|
||||
|
||||
def octave_band_limits(x):
|
||||
|
||||
b = 1
|
||||
|
||||
# Exact midband frequency
|
||||
fm = G**(x/b)*fr
|
||||
|
||||
G_power_values_pos = [0, 1/8, 1/4, 3/8, 1/2, 1/2, 1, 2, 3, 4]
|
||||
G_power_values_neg = [-i for i in G_power_values_pos]
|
||||
G_power_values_neg.reverse()
|
||||
G_power_values = G_power_values_neg[:-1] + G_power_values_pos
|
||||
|
||||
mininf = -1e300
|
||||
|
||||
lower_limits_pos = [-0.3, -0.4, -0.6, -1.3, -5.0, -5.0] + 4*[mininf]
|
||||
lower_limits_neg = lower_limits_pos[:]
|
||||
lower_limits_neg.reverse()
|
||||
lower_limits = np.asarray(lower_limits_neg[:-1] + lower_limits_pos)
|
||||
|
||||
upper_limits_pos = [0.3]*5 + [-2, -17.5, -42, -61, -70]
|
||||
upper_limits_neg = upper_limits_pos[:]
|
||||
upper_limits_neg.reverse()
|
||||
upper_limits = np.asarray(upper_limits_neg[:-1] + upper_limits_pos)
|
||||
|
||||
freqs = fm*G**np.asarray(G_power_values)
|
||||
|
||||
return freqs, upper_limits, lower_limits
|
||||
|
||||
|
||||
if __name__ == '__main__':
|
||||
|
||||
from asceefigs.plot import close, Figure
|
||||
close('all')
|
||||
freqs, upper_limits, lower_limits = octave_band_limits(0)
|
||||
|
||||
f = Figure()
|
||||
f.semilogx(freqs, lower_limits)
|
||||
f.semilogx(freqs, upper_limits)
|
||||
|
||||
f.ylim(-80, 1)
|
||||
@ -106,8 +106,7 @@ def C_fir_design():
|
||||
|
||||
|
||||
def show_Afir():
|
||||
from asceefigs.plot import close, Figure
|
||||
close('all')
|
||||
from asceefig.plot import Figure
|
||||
|
||||
fs = 48000.
|
||||
freq_design = np.linspace(0, 17e3, 3000)
|
||||
@ -133,8 +132,7 @@ def show_Afir():
|
||||
|
||||
|
||||
def show_Cfir():
|
||||
from asceefigs.plot import close, Figure
|
||||
close('all')
|
||||
from asceefig.plot import Figure
|
||||
|
||||
fs = 48000.
|
||||
freq_design = np.linspace(0, 17e3, 3000)
|
||||
|
||||
@ -38,8 +38,6 @@ class lasp_shelve:
|
||||
if lasp_shelve.refcount == 0:
|
||||
lasp_shelve.shelve.close()
|
||||
lasp_shelve.shelve = None
|
||||
|
||||
|
||||
|
||||
# Reference sound pressure level
|
||||
P_REF = 2e-5
|
||||
@ -77,7 +75,6 @@ class Window:
|
||||
def getCurrent(cb):
|
||||
return Window.types[cb.currentIndex()]
|
||||
|
||||
|
||||
class TimeWeighting:
|
||||
none = (None, 'Raw (no time weighting)')
|
||||
uufast = (1e-4, '0.1 ms')
|
||||
@ -105,7 +102,6 @@ class TimeWeighting:
|
||||
def getCurrent(cb):
|
||||
return TimeWeighting.types[cb.currentIndex()]
|
||||
|
||||
|
||||
class FreqWeighting:
|
||||
"""
|
||||
Frequency weighting types
|
||||
@ -132,7 +128,6 @@ class FreqWeighting:
|
||||
def getCurrent(cb):
|
||||
return FreqWeighting.types[cb.currentIndex()]
|
||||
|
||||
|
||||
def getTime(fs, N, start=0):
|
||||
"""
|
||||
Return a time array for given number of points and sampling frequency.
|
||||
@ -145,7 +140,6 @@ def getTime(fs, N, start=0):
|
||||
assert N > 0 and fs > 0
|
||||
return np.linspace(start, start + N/fs, N, endpoint=False)
|
||||
|
||||
|
||||
def getFreq(fs, nfft):
|
||||
"""
|
||||
return an array of frequencies for single-sided spectra
|
||||
|
||||
@ -3,22 +3,68 @@
|
||||
"""!
|
||||
Author: J.A. de Jong - ASCEE
|
||||
|
||||
Provides the FIR implementation of the octave filter bank
|
||||
Provides the implementations of (fractional) octave filter banks
|
||||
|
||||
"""
|
||||
__all__ = ['FirOctaveFilterBank', 'FirThirdOctaveFilterBank']
|
||||
__all__ = ['FirOctaveFilterBank', 'FirThirdOctaveFilterBank',
|
||||
'OverallFilterBank', 'SosOctaveFilterBank',
|
||||
'SosThirdOctaveFilterBank']
|
||||
|
||||
from .filter.filterbank_design import OctaveBankDesigner, ThirdOctaveBankDesigner
|
||||
from .wrappers import Decimator, FilterBank as pyxFilterBank
|
||||
from .filter.filterbank_design import (OctaveBankDesigner,
|
||||
ThirdOctaveBankDesigner)
|
||||
from .wrappers import (Decimator, FilterBank as pyxFilterBank,
|
||||
SosFilterBank as pyxSosFilterBank)
|
||||
import numpy as np
|
||||
|
||||
|
||||
class OverallFilterBank:
|
||||
"""
|
||||
Dummy type filter bank. Does nothing special, only returns output in a
|
||||
sensible way
|
||||
"""
|
||||
|
||||
def __init__(self, fs):
|
||||
"""
|
||||
Initialize overall filter bank
|
||||
"""
|
||||
self.fs = fs
|
||||
self.N = 0
|
||||
self.xs = [0]
|
||||
|
||||
def filter_(self, data):
|
||||
"""
|
||||
Filter input data
|
||||
"""
|
||||
assert data.ndim == 2
|
||||
assert data.shape[1] == 1, "invalid number of channels, should be 1"
|
||||
|
||||
if data.shape[0] == 0:
|
||||
return {}
|
||||
|
||||
# Output given as a dictionary with x as the key
|
||||
output = {}
|
||||
|
||||
tstart = self.N / self.fs
|
||||
Ncur = data.shape[0]
|
||||
tend = tstart + Ncur / self.fs
|
||||
|
||||
t = np.linspace(tstart, tend, Ncur, endpoint=False)
|
||||
self.N += Ncur
|
||||
|
||||
output['Overall'] = {'t': t, 'data': data, 'x': 0}
|
||||
return output
|
||||
|
||||
def decimation(self, x):
|
||||
return [1]
|
||||
|
||||
|
||||
class FirFilterBank:
|
||||
"""
|
||||
Single channel octave filter bank implementation
|
||||
Single channel (fractional) octave filter bank implementation, based on FIR
|
||||
filters and sample rate decimation.
|
||||
"""
|
||||
|
||||
def __init__(self, fs):
|
||||
def __init__(self, fs, xmin, xmax):
|
||||
"""
|
||||
Initialize a OctaveFilterBank object.
|
||||
|
||||
@ -29,7 +75,10 @@ class FirFilterBank:
|
||||
assert np.isclose(fs, 48000), "Only sampling frequency" \
|
||||
" available is 48 kHz"
|
||||
|
||||
maxdecimation = self.decimation(self.xs[0])
|
||||
self.fs = fs
|
||||
self.xs = list(range(xmin, xmax + 1))
|
||||
|
||||
maxdecimation = self.designer.firDecimation(self.xs[0])
|
||||
self.decimators = []
|
||||
for dec in maxdecimation:
|
||||
self.decimators.append(Decimator(1, dec))
|
||||
@ -43,7 +92,7 @@ class FirFilterBank:
|
||||
self.filterbanks = []
|
||||
# Sort the x values in categories according to the required decimation
|
||||
for x in self.xs:
|
||||
dec = self.decimation(x)
|
||||
dec = self.designer.firDecimation(x)
|
||||
if len(dec) == 1 and dec[0] == 1:
|
||||
xs_d1.append(x)
|
||||
elif len(dec) == 1 and dec[0] == 4:
|
||||
@ -60,24 +109,25 @@ class FirFilterBank:
|
||||
xs_all = [xs_d1, xs_d4, xs_d16, xs_d64, xs_d256]
|
||||
for xs in xs_all:
|
||||
nominals_txt = []
|
||||
firs = np.empty((self.L, len(xs)), order='F')
|
||||
for i, x in enumerate(xs):
|
||||
# These are the filters that do not require lasp_decimation
|
||||
# prior to filtering
|
||||
nominals_txt.append(self.nominal_txt(x))
|
||||
firs[:, i] = self.createFirFilter(fs, x)
|
||||
filterbank = {'fb': pyxFilterBank(firs, 1024),
|
||||
'xs': xs,
|
||||
'nominals': nominals_txt}
|
||||
self.filterbanks.append(filterbank)
|
||||
if len(xs) > 0:
|
||||
firs = np.empty((self.designer.firFilterLength, len(xs)), order='F')
|
||||
for i, x in enumerate(xs):
|
||||
# These are the filters that do not require lasp_decimation
|
||||
# prior to filtering
|
||||
nominals_txt.append(self.designer.nominal_txt(x))
|
||||
firs[:, i] = self.designer.createFirFilter(fs, x)
|
||||
filterbank = {'fb': pyxFilterBank(firs, 1024),
|
||||
'xs': xs,
|
||||
'nominals': nominals_txt}
|
||||
self.filterbanks.append(filterbank)
|
||||
|
||||
# Sample input counter.
|
||||
self.N = 0
|
||||
|
||||
# Filter output counters
|
||||
self.dec = [1, 4, 16, 64, 256]
|
||||
|
||||
# These intial delays are found experimentally using a toneburst
|
||||
# Filter output counters
|
||||
# These intial delays are found 'experimentally' using a toneburst
|
||||
# response.
|
||||
self.Nf = [915, 806, 780, 582, 338]
|
||||
|
||||
@ -105,8 +155,9 @@ class FirFilterBank:
|
||||
|
||||
t = np.linspace(tstart, tend, Nf, endpoint=False)
|
||||
self.Nf[dec_stage] += Nf
|
||||
for i, nom in enumerate(self.filterbanks[dec_stage]['nominals']):
|
||||
output[nom] = {'t': t, 'data': filtered[:, [i]]}
|
||||
for i, nom_txt in enumerate(self.filterbanks[dec_stage]['nominals']):
|
||||
x = self.designer.nominal_txt_tox(nom_txt)
|
||||
output[nom_txt] = {'t': t, 'data': filtered[:, [i]], 'x': x}
|
||||
|
||||
return output
|
||||
|
||||
@ -122,36 +173,141 @@ class FirFilterBank:
|
||||
|
||||
# Output given as a dictionary with x as the key
|
||||
output = {}
|
||||
output_unsorted = {}
|
||||
self.N += data.shape[0]
|
||||
|
||||
output = {**output, **self.filterd(0, data)}
|
||||
output_unsorted = {**output_unsorted, **self.filterd(0, data)}
|
||||
|
||||
for i in range(len(self.decimators)):
|
||||
dec_stage = i+1
|
||||
if data.shape[0] > 0:
|
||||
# Apply a decimation stage
|
||||
data = self.decimators[i].decimate(data)
|
||||
output = {**output, **self.filterd(dec_stage, data)}
|
||||
output_unsorted = {**output_unsorted,
|
||||
**self.filterd(dec_stage, data)}
|
||||
|
||||
# Create sorted output
|
||||
for x in self.xs:
|
||||
nom_txt = self.designer.nominal_txt(x)
|
||||
output[nom_txt] = output_unsorted[nom_txt]
|
||||
|
||||
return output
|
||||
|
||||
def decimation(self, x):
|
||||
return self.designer.firDecimation(x)
|
||||
|
||||
class FirOctaveFilterBank(FirFilterBank, OctaveBankDesigner):
|
||||
|
||||
class FirOctaveFilterBank(FirFilterBank):
|
||||
"""
|
||||
Filter bank which uses FIR filtering for each octave frequency band
|
||||
"""
|
||||
|
||||
def __init__(self, fs):
|
||||
OctaveBankDesigner.__init__(self)
|
||||
FirFilterBank.__init__(self, fs)
|
||||
def __init__(self, fs, xmin, xmax):
|
||||
self.designer = OctaveBankDesigner()
|
||||
FirFilterBank.__init__(self, fs, xmin, xmax)
|
||||
|
||||
|
||||
class FirThirdOctaveFilterBank(FirFilterBank, ThirdOctaveBankDesigner):
|
||||
class FirThirdOctaveFilterBank(FirFilterBank):
|
||||
"""
|
||||
Filter bank which uses FIR filtering for each one-third octave frequency
|
||||
band.
|
||||
"""
|
||||
|
||||
def __init__(self, fs):
|
||||
ThirdOctaveBankDesigner.__init__(self)
|
||||
FirFilterBank.__init__(self, fs)
|
||||
def __init__(self, fs, xmin, xmax):
|
||||
self.designer = ThirdOctaveBankDesigner(fs)
|
||||
FirFilterBank.__init__(self, fs, xmin, xmax)
|
||||
|
||||
|
||||
class SosFilterBank:
|
||||
def __init__(self, fs, xmin, xmax):
|
||||
"""
|
||||
Initialize a second order sections filterbank
|
||||
|
||||
Args:
|
||||
fs: Sampling frequency [Hz]
|
||||
xmin: Minimum value for the bands
|
||||
xmax: Maximum value for the bands
|
||||
"""
|
||||
self.fs = fs
|
||||
self.xs = list(range(xmin, xmax + 1))
|
||||
nfilt = len(self.xs)
|
||||
self._fb = pyxSosFilterBank(nfilt, 5)
|
||||
for i, x in enumerate(self.xs):
|
||||
sos = self.designer.createSOSFilter(x)
|
||||
self._fb.setFilter(i, sos)
|
||||
|
||||
self.xmin = xmin
|
||||
self.xmax = xmax
|
||||
self.N = 0
|
||||
|
||||
def filter_(self, data):
|
||||
"""
|
||||
Filter input data
|
||||
"""
|
||||
assert data.ndim == 2
|
||||
assert data.shape[1] == 1, "invalid number of channels, should be 1"
|
||||
|
||||
if data.shape[0] == 0:
|
||||
return {}
|
||||
|
||||
filtered_data = self._fb.filter_(data)
|
||||
|
||||
# Output given as a dictionary with nom_txt as the key
|
||||
output = {}
|
||||
|
||||
tstart = self.N / self.fs
|
||||
Ncur = data.shape[0]
|
||||
tend = tstart + Ncur / self.fs
|
||||
|
||||
t = np.linspace(tstart, tend, Ncur, endpoint=False)
|
||||
self.N += Ncur
|
||||
|
||||
for i, x in enumerate(self.xs):
|
||||
# '31.5' to '16k'
|
||||
nom_txt = self.designer.nominal_txt(x)
|
||||
output[nom_txt] = {'t': t, 'data': filtered_data[:, [i]], 'x': x}
|
||||
|
||||
return output
|
||||
|
||||
def decimation(self, x):
|
||||
return [1]
|
||||
|
||||
|
||||
class SosThirdOctaveFilterBank(SosFilterBank):
|
||||
"""
|
||||
Filter bank which uses FIR filtering for each one-third octave frequency
|
||||
band.
|
||||
"""
|
||||
|
||||
def __init__(self, fs, xmin, xmax):
|
||||
"""
|
||||
Initialize a second order sections filterbank.
|
||||
|
||||
Args:
|
||||
fs: Sampling frequency [Hz]
|
||||
xmin: Minimum value for the bands
|
||||
xmax: Maximum value for the bands
|
||||
"""
|
||||
self.designer = ThirdOctaveBankDesigner(fs)
|
||||
SosFilterBank.__init__(self, fs, xmin, xmax)
|
||||
|
||||
|
||||
class SosOctaveFilterBank(SosFilterBank):
|
||||
"""
|
||||
Filter bank which uses FIR filtering for each one-third octave frequency
|
||||
band.
|
||||
"""
|
||||
|
||||
def __init__(self, fs, xmin, xmax):
|
||||
"""
|
||||
Initialize a second order sections filterbank.
|
||||
|
||||
Args:
|
||||
fs: Sampling frequency [Hz]
|
||||
xmin: Minimum value for the bands
|
||||
xmax: Maximum value for the bands
|
||||
"""
|
||||
self.designer = OctaveBankDesigner(fs)
|
||||
SosFilterBank.__init__(self, fs, xmin, xmax)
|
||||
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user