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81 lines
2.1 KiB
Python
81 lines
2.1 KiB
Python
import cmsisdsp as dsp
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import cmsisdsp.fixedpoint as f
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import numpy as np
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from scipy import signal
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import matplotlib.pyplot as plt
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import scipy.fft
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import colorama
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from colorama import init,Fore, Back, Style
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from numpy.testing import assert_allclose
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init()
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def printTitle(s):
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print("\n" + Fore.GREEN + Style.BRIGHT + s + Style.RESET_ALL)
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def printSubTitle(s):
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print("\n" + Style.BRIGHT + s + Style.RESET_ALL)
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def chop(A, eps = 1e-6):
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B = np.copy(A)
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B[np.abs(A) < eps] = 0
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return B
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nb = 32
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signal = np.cos(2 * np.pi * np.arange(nb) / nb)*np.cos(0.2*2 * np.pi * np.arange(nb) / nb)
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ref=scipy.fft.rfft(signal)
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invref = scipy.fft.irfft(ref)
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print(f"ref length = {len(ref)}")
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print(ref)
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# Convert ref to CMSIS-DSP format
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referenceFloat=np.zeros(2*len(ref))
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print(f"referenceFloat length = {len(referenceFloat)}")
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# Replace complex datatype by real datatype
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referenceFloat[0::2] = np.real(ref)
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referenceFloat[1::2] = np.imag(ref)
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# Copy Nyquist frequency value into first
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# sample.This is just a storage trick so that the
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# output of the RFFT has same length as input
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# It is legacy behavior that we need to keep
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# for backward compatibility but it is not
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# very pretty
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#referenceFloat[1] = np.real(ref[-1])
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rifftQ31=dsp.arm_rfft_instance_q31()
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status=dsp.arm_rfft_init_q31(rifftQ31,nb,1,1)
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# Apply CMSIS-DSP scaling
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referenceQ31 = f.toQ31(referenceFloat / nb)
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resultQ31 = dsp.arm_rfft_q31(rifftQ31,referenceQ31)
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resultF = f.Q31toF32(resultQ31)
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print(f"resultF length = {len(resultF)}")
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assert_allclose(invref/nb,resultF,atol=1e-6)
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signalQ31 = f.toQ31(signal)
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rfftQ31=dsp.arm_rfft_instance_q31()
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status=dsp.arm_rfft_init_q31(rfftQ31,nb,0,1)
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resultQ31 = dsp.arm_rfft_q31(rfftQ31,signalQ31)
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print(len(resultQ31))
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print(2*nb)
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resultF = f.Q31toF32(resultQ31) * nb
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def compareWithConjugatePart(r):
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res = r[0::2] + 1j * r[1::2]
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conjPart = res[nb:nb//2:-1].conj()
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refPart = res[1:nb//2]
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assert(np.equal(refPart , conjPart).all())
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compareWithConjugatePart(resultF)
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res = resultF[0::2] + 1j * resultF[1::2]
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print(res)
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print(res[0:nb//2+1])
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print(res[0:nb//2+1].shape) |