78 lines
2.3 KiB
Python
78 lines
2.3 KiB
Python
"""
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This script checks whether the 3rd octave equalizer is norm compliant.
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Created on Tue Dec 31 14:43:19 2019
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@author: anne
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"""
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from lasp.filter import (ThirdOctaveBankDesigner)
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import matplotlib.pyplot as plt
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import numpy as np
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from scipy.signal import freqz, iirdesign, sosfreqz, butter, cheby2
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plt.close('all')
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# %% Run check
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def check_one(fs):
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"""Check for fs = fs"""
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# Create filter bank
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nsections = 5 # filter property
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designer = ThirdOctaveBankDesigner(fs)
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# Test
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xmin = designer.nominal_txt_tox('25') # lowest highest band, nominal name
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xmax = designer.nominal_txt_tox('20k') # highest band
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compliant = True # remains True if all filters comply
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fnyq = fs/2
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fll = designer.fl(xmin) / 1.1 # plot limits
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fuu = designer.fu(xmax) * 1.1
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fig = plt.figure()
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plt.xlabel('f (Hz)')
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plt.ylabel('Magnitude (dB)')
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for x in range(xmin, xmax+1): # loop over bands
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fl = designer.fl(x) # lower cut off
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fu = designer.fu(x) # upper
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fln = fl/fnyq # lower cutoff, normalized [0, 1]
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fun = fu/fnyq # upper
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sos = designer.createSOSFilter(x)
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fnorm, h = sosfreqz(sos, worN=2**18, whole=False)
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freq = fnorm*fnyq/np.pi
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h_dB = 20*np.log10(np.abs(h) + np.finfo(float).eps)
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if not designer.testStandardCompliance(x, freq, h_dB):
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print('==============================')
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print(designer.nominal_txt(x), ' does not comply\n')
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compliant = False
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plt.semilogx(freq, h_dB)
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# Upper / lower limits
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freqlim, ulim, llim = designer.band_limits(x)
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plt.semilogx(freqlim, ulim)
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plt.semilogx(freqlim, llim)
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plt.ylim(-5, 1)
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plt.xlim(fll, fuu)
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print(f"Passed test : {compliant} for fs = {fs} Hz")
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return compliant
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if __name__ == "__main__":
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# Make list of fs to be tested
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# Taken from https://en.wikipedia.org/wiki/Sampling_(signal_processing)
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fs_all = [8000, 11025, 16000, 22050, 32000, 37800, 44056, 44100, 47250,
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48000, 50000, 50400, 64000, 88200, 96000, 176400, 192000, 352800]
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allcompliant = True
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for fs in fs_all:
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compliant = check_one(fs)
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if not compliant:
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allcompliant = False
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print(f"\n\nAll passed test : {allcompliant}")
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