Example Python script to implement the Phasemeter (plotting)

#
# pymoku example: Plotting Phasemeter
#
# This example demonstrates how you can configure the Phasemeter instrument
# and stream dual-channel samples of the form [fs, f, count, phase, I, Q].
# The signal amplitude is calculated using these samples, and plotted for
# real-time viewing.
#
# (c) 2019 Liquid Instruments Pty. Ltd.
#
from pymoku import Moku, StreamException
from pymoku.instruments import Phasemeter
import math
import numpy
import matplotlib.pyplot as plt

# Connect to your Moku by its device name
# Alternatively, use Moku.get_by_serial('#####') or Moku('192.168.###.###')
m = Moku.get_by_name('Moku')

try:
 i = m.deploy_or_connect(Phasemeter)

 # Set samplerate to slow mode ~30Hz
 i.set_samplerate('slow')

 # Set up signal generator outputs
 # Channel 1 - 5MHz, 0.5Vpp Sinewave
 # Channel 2 - 10MHz, 1.0Vpp Sinewave
 i.gen_sinewave(1, 0.5, 5e6)
 i.gen_sinewave(2, 1.0, 10e6)

 # Restart the phase-lock loop for both channels, and automatically
 # resolve the starting frequency (as opposed to manually setting a seed
 # frequency)
 i.auto_acquire()

 # Stop any existing streaming session and start a new one
 # Logging session:
 # Duration - 20 sec
 # Channel 1 - ON, Channel 2 - ON
 i.stop_stream_data()
 i.start_stream_data(duration=20, ch1=True, ch2=True)

 # Set up plotting configuration
 plot_points = 500

 ydata1 = [None] * plot_points
 line1, = plt.plot(ydata1)

 ydata2 = [None] * plot_points
 line2, = plt.plot(ydata2)

 xtent = -1 * (i.get_timestep() * (plot_points - 1))
 xdata = numpy.linspace(xtent, 0, plot_points)

 plt.ion()
 plt.show()
 plt.grid(b=True)
 ax = plt.gca()
 ax.get_yaxis().get_major_formatter().set_useOffset(False)
 plt.xlim([xtent, 0])
 plt.ylabel('Amplitude (V)')
 plt.xlabel('Time (s)')

 # This loop gets and plots the samples being streamed by the Phasemeter
 # over the network
 while True:

 # Get samples off the network
 data = i.get_stream_data()
 # If data is empty then the streaming session has completed
 if not any(data):
 break

 # Process the retrieved samples from both channels
 # Each sample has format [fs, f, count, phase, I, Q]
 # Convert I,Q to amplitude and append to line graph
 ch1_samples = data[0]
 ydata1 += [math.sqrt(s[4]**2 + s[5]**2) for s in data[0]]
 ydata2 += [math.sqrt(s[4]**2 + s[5]**2) for s in data[1]]

 ydata1 = ydata1[-plot_points:]
 ydata2 = ydata2[-plot_points:]

 # Update the plotted line graphs with the new data
 line1.set_ydata(ydata1)
 line1.set_xdata(xdata)

 line2.set_ydata(ydata2)
 line2.set_xdata(xdata)

 ax.relim()
 ax.autoscale_view()
 plt.pause(0.001)
 plt.draw()

 i.stop_stream_data()

except StreamException as e:
 print("Error occured: %s" % e)
finally:
 m.close()