73 lines
2.6 KiB
Python
73 lines
2.6 KiB
Python
#!/usr/bin/env python3
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"""verify_lut.py — непараметрическая LUT-кривая, форма B.10. rmse."""
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import numpy as np
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from scipy.interpolate import PchipInterpolator
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FS = 44100.0
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DEPTH = 0.8639736175537109
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QS = [0.1, 0.2, 0.3, 0.5, 0.7, 1.0, 1.5, 2.0, 3.0, 5.0, 10.0]
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DUAL = np.array([(10.220, 15.224), (10.219, 13.963), (10.219, 12.947),
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(10.219, 11.725), (10.218, 11.119), (10.216, 10.689),
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(10.210, 10.412), (10.203, 10.305), (10.182, 10.225),
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(10.113, 10.183), (9.822, 10.165)])
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FCS = [800.0, 900.0, 950.0, 1000.0, 1050.0, 1100.0, 1200.0]
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T1KQ = np.array([7.868, 8.536, 8.726, 8.788, 8.729, 8.575, 8.115])
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T1K = np.array([14.548, 15.332, 15.553, 15.626, 15.557, 15.378, 14.840])
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L_DUAL = 10 ** (-7.142 / 20)
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L_T1KQ = 10 ** (-18.063 / 20)
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L_T1K = 1.0
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TILT = {500: 1.414, 1000: 1.454, 2000: 1.795}
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Q, G = 0.900, 4.132
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LUTX = np.array([-0.750, -0.500, -0.250, 0.000, 0.250, 0.500, 0.750, 1.000])
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LUTY = np.array([0.4453, 0.4551, 0.4784, 0.5041, 0.5331, 0.5715, 0.6574, 0.6636])
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lut = PchipInterpolator(LUTX, LUTY)
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def res_at(ft, fc, Q, g):
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w0 = fc * 2 * np.pi / FS
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c, s = np.cos(w0), np.sin(w0)
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p = (s * 0.5) / Q
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a, a2 = p * g, p / g
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A = [a + 1, -2 * c, 1 - a]
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B = [a2 + 1, -2 * c, 1 - a2]
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w = 2 * np.pi * ft / FS
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z = np.exp(-1j * w)
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return np.abs(2.0 * (B[0] + B[1] * z + B[2] * z * z) /
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(A[0] + A[1] * z + A[2] * z * z))
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def red(x, tilt):
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C = DEPTH * tilt * lut(x)
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return -20 * np.log10(max(1 - C, 1e-9))
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def run():
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preds = []
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meas = []
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print('--- dual_b1q ---')
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for i, q in enumerate(QS):
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for f, m in ((500, DUAL[i, 0]), (2000, DUAL[i, 1])):
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r = res_at(f, 500, q, G)
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p = red(np.log10(L_DUAL / r), TILT[f])
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preds.append(p); meas.append(m)
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print(f'q={q:5.1f} f={int(f)} {m:6.3f}/{p:6.3f} ({p - m:+.3f})')
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print('--- t1kq -18dB ---')
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for i, fc in enumerate(FCS):
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r = res_at(1000, fc, 0.9999978, G)
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p = red(np.log10(L_T1KQ / r), TILT[1000])
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preds.append(p); meas.append(T1KQ[i])
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print(f'fc={fc:5.0f} {T1KQ[i]:6.3f}/{p:6.3f} ({p - T1KQ[i]:+.3f})')
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print('--- t1k 0dB ---')
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for i, fc in enumerate(FCS):
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r = res_at(1000, fc, 0.9999978, G)
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p = red(np.log10(L_T1K / r), TILT[1000])
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preds.append(p); meas.append(T1K[i])
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print(f'fc={fc:5.0f} {T1K[i]:6.3f}/{p:6.3f} ({p - T1K[i]:+.3f})')
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preds = np.array(preds); meas = np.array(meas)
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print(f'\nTOTAL rmse={np.sqrt(np.mean((preds - meas) ** 2)):.4f} dB')
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if __name__ == '__main__':
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run()
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