希尔伯特变换计算瞬时频率

如何解决希尔伯特变换计算瞬时频率

我需要计算嵌入在系统中的瞬时频率与时间相对应。

这些是我写的代码：

from scipy import signal
import matplotlib.pyplot as plt
import numpy as np
from scipy.signal import hilbert,chirp


## Define the signal

# Sampling Frequency                      
Fs = 1e4  

# 0-10 seconds of data,with frequencies 50Hz and 100Hz
N1 = (1e5)
time1 = np.arange(N1) / float(Fs)          
x1 = 1*np.sin(2*np.pi*50*time1)  + 0.01*np.sin(2*np.pi*100*time1)


# Pot time data
plt.figure(figsize=(10,10))  
plt.subplot(211)
plt.plot(time1,x1)
plt.title('Time Data')
plt.ylabel('Amplitude [A]')
plt.xlabel('Time [sec]')


# Hilbert transform
analytic_signal = hilbert(x1)
amplitude_envelope = np.abs(analytic_signal)
instantaneous_phase = np.unwrap(np.angle(analytic_signal))
instantaneous_frequency = ((np.diff(instantaneous_phase) /  (2.0*np.pi) * Fs)).round(decimals=2)


# Plot instantaneous_frequency
plt.subplot(212)
plt.plot(time1[1:],instantaneous_frequency,'m',linewidth=1) 
plt.xlabel('Time (s)')
plt.ylabel('Freq (Hz)')
plt.title('Instantaneous Frequency')
plt.grid(True,color = "green",linewidth = "1",linestyle = "-.")
plt.ylim(0,200)

plt.show()

结果如图：

在此图中，我无法看到 100 Hz 频率。

有人可以让我知道我哪里出错了吗？