[2021 Fall] Final Exam - Question 4¶

Course: AP3021

In [1]:

import numpy as np
import matplotlib.pyplot as plt
import pandas as pd
from scipy.fft import fft, fftfreq, ifft

import numpy as np import matplotlib.pyplot as plt import pandas as pd from scipy.fft import fft, fftfreq, ifft

讀檔

In [2]:

df = pd.read_fwf('./data/test.dat.rtf',skiprows=8)

df = pd.read_fwf('./data/test.dat.rtf',skiprows=8)

In [3]:

time=df.iloc[:, 1]
data=df.iloc[:, 7]
#print(df)
data=data.to_numpy()
#print(time)
#print(data)
n=48 #data amount
x = np.arange(0, n, 1)

plt.plot(data)
plt.title("zenith total delay")
plt.ylabel("zenith total delay")
plt.xlabel("Time (30min interval)")
plt.show()

time=df.iloc[:, 1] data=df.iloc[:, 7] #print(df) data=data.to_numpy() #print(time) #print(data) n=48 #data amount x = np.arange(0, n, 1) plt.plot(data) plt.title("zenith total delay") plt.ylabel("zenith total delay") plt.xlabel("Time (30min interval)") plt.show()

In [4]:

y1= np.zeros(n, dtype=complex)  #轉完的資料為complex形式
yf = fft(data)

k=1                #晝、夜
y1[0]=yf[0]
y1[1:1+k-1]=yf[1:1+k-1]
y1[n-k:n]=yf[n-k:n]         
yt = ifft(y1,n)          

plt.title('Zenith total delay')
plt.ylabel('Zenith total delay')
plt.xlabel('Time (30min interval)')
#plt.axis([0.0, 20.0, 0.0, 6.0])
plt.plot(data, label = "Origional")
plt.plot(yt, label = "FFT")
plt.grid(True)
#plt.xticks(range(0, 21, 1))
#plt.yticks(range(0, 7, 1))
plt.legend()
#plt.savefig('Windspeed_High_Relation_fft.png')
plt.show()

y1= np.zeros(n, dtype=complex) #轉完的資料為complex形式 yf = fft(data) k=1 #晝、夜 y1[0]=yf[0] y1[1:1+k-1]=yf[1:1+k-1] y1[n-k:n]=yf[n-k:n] yt = ifft(y1,n) plt.title('Zenith total delay') plt.ylabel('Zenith total delay') plt.xlabel('Time (30min interval)') #plt.axis([0.0, 20.0, 0.0, 6.0]) plt.plot(data, label = "Origional") plt.plot(yt, label = "FFT") plt.grid(True) #plt.xticks(range(0, 21, 1)) #plt.yticks(range(0, 7, 1)) plt.legend() #plt.savefig('Windspeed_High_Relation_fft.png') plt.show()

/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/matplotlib/cbook/__init__.py:1340: ComplexWarning: Casting complex values to real discards the imaginary part
  return np.asarray(x, float)

---

Last update: 2024-04-27