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BasicFFT.py
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BasicFFT.py
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from __future__ import division, print_function
import numpy as np
import scipy.fftpack
def basicFFT(rate, dataArray):
N = len(dataArray)
freqSpacing = rate/N
rawFFT = scipy.fftpack.fft(dataArray)
positiveFreqs = np.abs(rawFFT[:N//2])
return positiveFreqs
def maxFFT(rate, dataArray):
N = len(dataArray)
freqSpacing = rate/N
rawFFT = scipy.fftpack.fft(dataArray)
positiveFreqs = np.abs(rawFFT[:N//2])
maxAmplitude = np.amax(positiveFreqs,axis=0)
epsilon = 0.05*maxAmplitude
peakIndex = np.argwhere(abs(positiveFreqs-maxAmplitude)<epsilon)
freq = freqSpacing*peakIndex
return freq.flatten()
def intervalFFT(rate, dataArray, msInterval):
samplesPerInterval = int(msInterval / 1000 * rate)
N = len(dataArray)
intervals = []
for startIndex in range(0, N - samplesPerInterval, samplesPerInterval):
intervals.append(dataArray[startIndex:startIndex+samplesPerInterval])
frequencies = []
for interval in intervals:
frequencies.append(maxFFT(rate, interval))
return frequencies