added FFT using numpy

This commit is contained in:
Ryan Tang 2024-03-14 17:26:33 -04:00
parent 2429d5d1dd
commit ad667bf2e5

50
test.py
View File

@ -87,10 +87,13 @@ Query('WAVEFORM:FORMAT?')
[status, wfLen] = Query('WAVEFORM:STATUS?').split(',')
if status == "IDLE" and int(wfLen) >= 0 :
print("---- get waveform data")
start_time = time.time()
osc.write('WAVEFORM:DATA?')
binary = osc.read_bytes(int(wfSize) +11 + 1) #
end_time = time.time()
# print(binary)
duration = end_time - start_time
print("Duration for obtaining waveform:", duration, "seconds")
#---------- read data from internal memory, 1.12 million points, take like
# Write('STOP')
@ -133,5 +136,48 @@ header = binary[:11]
data_points = binary[11:]
# Decode the 1-byte data points
decoded_data = [byte for byte in data_points]
print("Decoded data:", decoded_data)
# print("Decoded data:", decoded_data)
#===================== FFT
import numpy as np
signal = np.array(decoded_data)
signal = signal[:-1]
timeStep = float(para[4])
sampling_rate = 1./timeStep # Sampling rate (Hz)
duration = wfSize * timeStep # Duration of signal (seconds)
num_samples = wfSize
timeList = np.linspace(0, duration, num_samples)
# Perform FFT
fft_result = np.fft.fft(signal)
frequencies = np.fft.fftfreq(num_samples, 1 / sampling_rate)
# Plot
import matplotlib.pyplot as plt
# Plot signal
plt.figure(figsize=(14, 6))
plt.subplot(1, 2, 1)
plt.plot(timeList*1e6, signal)
plt.title('Signal')
plt.xlabel('Time (us)')
plt.ylabel('Amplitude')
plt.grid(True)
# Plot FFT
plt.subplot(1, 2, 2)
# plt.plot(frequencies[:num_samples//2] / 1e6, np.abs(fft_result)[:num_samples//2])
plt.semilogy(frequencies[:num_samples//2] / 1e6, np.abs(fft_result)[:num_samples//2])
plt.title('FFT of Signal')
plt.xlabel('Frequency (MHz)')
plt.ylabel('Magnitude')
plt.grid(True)
plt.xlim(0, 100) # Set the X-range from 0 to 10 MHz
plt.tight_layout()
plt.show()