Source code for RCAIDE.Library.Methods.Noise.Common.convert_to_third_octave_band
# RCAIDE/Methods/Noise/Common/convert_to_third_octave_band.py
#
#
# Created: Jul 2023, M. Clarke
# ----------------------------------------------------------------------------------------------------------------------
# IMPORT
# ----------------------------------------------------------------------------------------------------------------------
# Python package imports
import numpy as np
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# Convert to Third Octave Band
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[docs]
def convert_to_third_octave_band(SPL,f,settings):
"""This method converts the SPL spectrum from blade harmonic passing frequency
to third octave spectrum
Assumptions:
N/A
Source:
Inputs:
SPL - sound pressure level [dB]
f - blade passing spectrum frequencies [Hz]
settings.
center_frequencies - center frequencies of the 1/3 octave spectrum [dB]
lower_frequencies - lower frequencies of the 1/3 octave spectrum [dB]
upper_frequencies - upper frequencies of the 1/3 octave spectrum [dB]
Outputs:
SPL_third_octave - SPL in the 1/3 octave spectrum [dB]
Properties Used:
N/A
"""
# unpack
cf = settings.center_frequencies
lf = settings.lower_frequencies
uf = settings.upper_frequencies
dim_cpt = len(SPL[:,0,0])
dim_mic = len(SPL[0,:,0])
num_cf = len(cf)
num_f = len(f[0,0,:])
uf_vals = np.tile(uf[None,None,:,None],(dim_cpt,dim_mic,1,num_f))
lf_vals = np.tile(lf[None,None,:,None],(dim_cpt,dim_mic,1,num_f))
f_vals = np.tile(f[:,:,None,:],(1,1,num_cf,1))
SPL_vals = np.tile(SPL[:,:,None,:],(1,1,num_cf,1))
upper_bool = (f_vals <= uf_vals)
lower_bool = (lf_vals <= f_vals)
boolean = np.logical_and(upper_bool,lower_bool)
SPL_array = boolean*SPL_vals
p_prefs = 10**(SPL_array/10)
SPL_third_octave = 10*np.log10(np.sum(boolean*p_prefs, axis =3))
SPL_third_octave[np.isinf(SPL_third_octave)] = 0
return SPL_third_octave
