Example Python script to implement the Spectrum Analyzer (plotting)

This example Python script shows how to setup Moku:Lab's Spectrum Analyzer instrument and how to plot the data in real time. This example is not compatible with Moku:Pro.

#
    # moku example: Plotting Spectrum Analyzer
    #
    # This example demonstrates how you can configure the Spectrum Analyzer
    # instrument and plot its spectrum data in real-time. 
    #
    # (c) 2021 Liquid Instruments Pty. Ltd.
    #
    
    import matplotlib.pyplot as plt
    from moku.instruments import SpectrumAnalyzer
    
    # Connect to your Moku by its ip address using SpectrumAnalyzer('192.168.###.###')
    # or by its serial number using SpectrumAnalyzer(serial=123)
    i = SpectrumAnalyzer('192.168.###.###', force_connect=False)
    
    try:
        # Configure the Spectrum Analyzer 
        i.set_span(frequency1=0, frequency2=30e3)
        i.disable_output(1)
        i.set_rbw('Auto')  # Auto-mode
        
        # Configure ADC inputs
        i.set_frontend(1, impedance='1MOhm', coupling='DC', range='10Vpp')
        i.set_frontend(2, impedance='1MOhm', coupling='DC', range='10Vpp')
    
        # Set up basic plot configurations
        line1, = plt.plot([])
        line2, = plt.plot([])
        plt.ion()
        plt.show()
        plt.grid(visible=True)
        plt.ylim([-120, 20])
        plt.autoscale(axis='x', tight=True)
    
        # Get an initial frame of data to set any frame-specific plot parameters
        frame = i.get_data()
    
        # Format the x-axis as a frequency scale
        ax = plt.gca()
    
        # Get and update the plot with new data
        while True:
            frame = i.get_data()
            
            # Set the frame data for each channel plot
            line1.set_ydata(frame['ch1'])
            line2.set_ydata(frame['ch2'])
            # Frequency axis shouldn't change, but to be sure
            line1.set_xdata(frame['frequency'])
            line2.set_xdata(frame['frequency'])
            # Ensure the frequency axis is a tight fit
            ax.relim()
            ax.autoscale_view()
    
            # Redraw the lines
            plt.draw()
            plt.pause(0.001)
    
    except Exception as e:
        print(f'Exception occurred: {e}')
    finally:
        # Close the connection to the Moku device
        # This ensures network resources and released correctly
        i.relinquish_ownership()