我有一个Matlab脚本,可以计算信号的DFT并绘制图表:
(数据可以在这里找到here)
clc; clear; close all;
fid = fopen('s.txt');
txt = textscan(fid,'%f');
s = cell2mat(txt);
nFFT = 100;
fs = 24000;
deltaF = fs/nFFT;
FFFT = [0:nFFT/2-1]*deltaF;
win = hann(length(s));
sw = s.*win;
FFT = fft(sw, nFFT)/length(s);
FFT = [FFT(1); 2*FFT(2:nFFT/2)];
absFFT = 20*log10(abs(FFT));
plot(FFFT, absFFT)
grid on
我努力将其翻译成Python代码,但无法得到相同的结果。
import numpy as np
from matplotlib import pyplot as plt
x = np.genfromtxt("s.txt", delimiter=' ')
nfft = 100
fs = 24000
deltaF = fs/nfft;
ffft = [n * deltaF for n in range(nfft/2-1)]
ffft = np.array(ffft)
window = np.hanning(len(x))
xw = np.multiply(x, window)
fft = np.fft.fft(xw, nfft)/len(x)
fft = fft[0]+ [2*fft[1:nfft/2]]
fftabs = 20*np.log10(np.absolute(fft))
plt.figure()
plt.plot(ffft, np.transpose(fftabs))
plt.grid()
我得到的图表(左边是Matlab,右边是Python):
![enter image description here](https://istack.dev59.com/pRiRG.webp)
[0:49]
与Python的range(49)
不同。在Python中,你会少一个数。(即range(49)
相当于[0:48]
) - Tasos Papastylianou