Electronics Explorer - Intro to the Arbitrary Waveform Generator, Oscilloscope, and Network Analyzer

  • Using the AWG, Oscilloscope, and Network Analyzer to observe the behavior of an RC circuit.

Introduction

This project is designed to familiarize the user with the Arbitrary Waveform Generator (AWG) and Oscilloscope instruments within the Digilent WaveForms software. A simple RC circuit will be built on the EE Board (Electronics Explorer Board). The AWG will be used to apply either a step input or sinusoidal input to the RC circuit. The Oscilloscope will be used to observe the circuit’s resulting behavior. In this project, we will look at generating a step response and a sinusoidal response in the time domain. We will also use the Network Analyzer to generate a sinusoidal response in the frequency domain.

Since this project primarily serves the purpose of familiarizing the user with the EE Board and WaveForms software so it will not discuss any background material on RC circuits and step/sinusoidal responses. However, the interested reader is recommended to visit the Digilent Learn Site, learn.digilentinc.com, to learn more about RC circuits and a wide variety of other electronics topics.

Materials

  • Electronics Explorer Board w/ Power Supply and USB cable
  • From the Starter Parts Kit:
    • 1.0kΩ Resistor
    • 0.0047μF Capacitor (4.7nF)
    • Jumper wires
  • WaveForms Software ( download) - WaveForms 3.5.4 is used in this tutorial

Procedures

Generate a Step Response in the Time Domain

  1. Connect the EE Board to your PC with the USB cable.
  2. Connect the board's external power supply and flip the Ready switch to the ON position.
  3. Build the circuit by connecting the DC channel on Scope 1 to AWG channel 1, the 1 kΩ resistor from AWG channel 1 to one side of the 4.7 nF capacitor, the DC channel on Scope 2 to the same row as the connected resistor and capacitor, and by wiring the unconnected side of the capacitor to ground.
    • The figure below shows the completed circuit.
  4. Launch the WaveForms Software. The Device Manager will pop up. Click your EExplorer on the list and click Select. The WaveForms main window will now appear.
  5. Click on the icon to open the Oscilloscope and on the icon to open the Arbitrary Waveform Generator.
  6. We are going to configure the Arbitrary Waveform Generator first. Configure the AWG with the following settings:
    • Step input
    • Frequency = 1kHz
    • Amplitude = 5V
    • Offset = 5V
    • Type = Square
    • Verify you have the correct settings by comparing your AWG window to the figure below.
  7. Next we will configure the Oscilloscope.
    • Trigger Settings: Mode to Auto, Source as Channel 1, Trigger Cond. as Falling, Trigger Level to 5V
    • On the right side of the screen, set Time Position = 20us
    • Time Base = 5 μs/div
    • Channel 1 & 2 Offsets to -6V by typing the values in
    • Channel 1 & 2 Ranges to 2V/div
    • Disable Channels 3 & 4 by clicking their respective check-boxes.
    • Verify your settings by comparing your window to the figure below.
  8. Go back to the AWG window and click either the Run or Run or the green arrow on the Wavegen tab to start the AWG. Return to the Oscilloscope Window and click Run here as well. The result is shown in the figure below. Note that Channels 1 and 2 correspond with the numbers listed on the SCOPE part of the EE Board itself.

Generate a Sinusoidal Response in the Time Domain

  1. This portion of the project will use the same circuit as the previous part. We will begin by making some quick changes to the AWG and Oscilloscope instruments.
  2. Return to the AWG window and apply the following settings:
    • Type = Sine
    • Frequency = 20kHz
    • Amplitude = 8V
    • Offset = 0V
    • Verify your settings with the image below.
  3. Next we will configure the Oscilloscope.
    • Trigger Settings: Mode to Auto, Source as Channel 1, Trigger Cond. as Rising, Trigger Level to 5V
    • On the right side of the screen, set Time Position = 0s
    • Time Base = 10us/div
    • Channel 1 & 2 Offsets to 0V
    • Channel 1 & 2 Ranges to 2V/div
    • Disable Channels 3 & 4 by clicking their respective check-boxes.
    • Verify your settings with the figure below.
  4. Go back to the AWG window and click Run AWG 1 or Run All. Return to the Oscilloscope Window and click Run here as well. The result is shown in the figure below.
  5. This part of the project will be continued to explore additional features of the WaveForms software. First, we are going to experiment with the measurement tool. Click the View dropdown menu on the toolbar and then select Measurements.
  6. A Measurements tab will open up next to the oscilloscope as shown in the next figure. Clicking Add will bring up a small window that gives you a variety of characteristics to measure on each channel, such as frequency, amplitude, period, etc. Browse around and try a few different ones to see how they work. Measurements will be taken when the oscilloscope is set to Run, and they also work when doing single data acquisitions.
  7. The next feature we are going to look at is the Zoom feature. Click the View dropdown menu on the toolbar and then select Add Zoom. An additional window will pop up showing a close up of a portion of the Oscilloscope window. You will notice the portion shown in the Zoom window has a box drawn around it in the Oscilloscope window. You can move this box as necessary by clicking and dragging in the Zoom window. The zoom box can be resized by clicking on the gear icon in the upper-right hand corner of the Zoom window and changing the H-range and V-range values. See the figure below for reference.
  8. Lastly, you can export data from WaveForms in a variety of formats. This is done by clicking the File dropdown menu in the toolbar and then clicking Export. Note, if you are using any additional tools, such as Measure, WaveForms will allow you to use the data from those tools as the source to export from. Data can be exported as either numerical data or images and WaveForms supports a variety of formats.

Generate a Sinusoidal Response in the Frequency Domain

  1. Again, we will continue using the same circuit for the last portion of this project.
  2. Return to the WaveForms main window. Click the Network icon to open the Network Analyzer. Set the Start frequency to 1kHz, the Stop frequency to 230kHz, Amplitude to 5V, and Samples to 100. On the right-hand side of the WaveForms GUI, in the Magnitude box set the Top to 10dB and the Range to 30dB, and set the Channel 1 Gain to 2X. Verify your settings with the figure below.
  3. Once you have the Network Analyzer configured, click “Run”. You should see the results shown below.