Retekess TD157 wireless paging system - signal with Python

 5.2.2021
Retekess TD157 wireless paging system - signal with Python

433.920 MHz, AM (ASK/OOK)
Python + Matplotlib/Scipy/Numpy
Signal recorded from IQ to AM with SDR#

import scipy.io.wavfile as wav
import scipy.signal as signal
import numpy as np
import matplotlib.pyplot as plt

fs, data = wav.read('am-rec.wav')

plt.figure(figsize=(13,4))
plt.grid(b=True, which='major', color='#666666', linestyle='-')
plt.minorticks_on()
plt.grid(b=True, which='minor', color='#999999', linestyle='-', alpha=0.2)
plt.plot(data)
plt.xlabel("Samples")
plt.ylabel("Amplitude")
plt.title("AM")
plt.show()

 

import scipy.io.wavfile as wav
import scipy.signal as signal
import numpy as np
import matplotlib.pyplot as plt

fs, data = wav.read('am-rec.wav')

asg = signal.hilbert(data)
ampenv = np.abs(asg)

plt.figure(figsize=(13,4))
plt.grid(b=True, which='major', color='#666666', linestyle='-')
plt.minorticks_on()
plt.grid(b=True, which='minor', color='#999999', linestyle='-', alpha=0.2)
plt.plot(ampenv)
plt.xlabel("Samples")
plt.ylabel("Amplitude")
plt.title("AM")
plt.show()

 

import scipy.io.wavfile as wav
import scipy.signal as signal
import numpy as np
import matplotlib.pyplot as plt

fs, data = wav.read('am-rec.wav')

asg = signal.hilbert(data)
ampenv = np.abs(asg)

range = (80, 180)
bins = 100
plt.figure(figsize=(10,4))
plt.grid(b=True, which='major', color='#666666', linestyle='-')
plt.minorticks_on()
plt.grid(b=True, which='minor', color='#999999', linestyle='-', alpha=0.2)
plt.hist(ampenv, bins, range, histtype = 'bar', rwidth = 0.8)
plt.title("AM")
plt.show()

IQ

import scipy.io.wavfile as wav
import scipy.signal as signal
import numpy as np
import matplotlib.pyplot as plt

fs, data = wav.read('iqdata.wav')

plt.figure(figsize=(11,4))
plt.grid(b=True, which='major', color='#666666', linestyle='-')
plt.minorticks_on()
plt.grid(b=True, which='minor', color='#999999', linestyle='-', alpha=0.2)
plt.plot(data)
plt.title("IQ")
plt.show()

GNU Radio