CN 05 (Diagramme de l'œil)

3 min read 4 months ago
Published on Apr 05, 2025 This response is partially generated with the help of AI. It may contain inaccuracies.

Introduction

This tutorial will guide you through the process of creating and interpreting an eye diagram, a vital tool in digital transmission used to evaluate the quality of received signals. By following these steps, you'll learn how to superimpose multiple periods of a digital signal on an oscilloscope or signal analyzer, enhancing your understanding of signal integrity in communication systems.

Step 1: Set Up Your Equipment

To begin, gather the necessary tools and prepare your workspace.

  • Equipment Required:

    • Oscilloscope or signal analyzer
    • Signal generator (if testing a specific signal)
    • Cables for connections
  • Setup Instructions:

    1. Connect the signal generator to the oscilloscope input.
    2. Ensure all cables are securely attached to avoid signal loss.
    3. Power on the oscilloscope and configure it to the appropriate settings for your digital signal.

Step 2: Generate the Digital Signal

Next, you'll need to create the digital signal that you will analyze.

  • Signal Generation Steps:
    1. Use the signal generator to create a digital waveform (e.g., square wave, pulse).
    2. Set the frequency and amplitude according to your requirements.
    3. Connect the output from the signal generator to the oscilloscope.

Step 3: Configure the Oscilloscope

Now, it's time to adjust the oscilloscope settings to properly visualize the eye diagram.

  • Oscilloscope Settings:
    1. Set the time base to capture multiple periods of the signal.
    2. Adjust the vertical scale to ensure the signal fits within the display.
    3. Use the trigger settings to stabilize the waveform on the screen.

Step 4: Capture the Eye Diagram

With everything set up, you can now capture the eye diagram.

  • Capturing Steps:
    1. Activate the persistence mode on the oscilloscope to overlay multiple signal periods.
    2. Allow the oscilloscope to collect data for several cycles of the signal.
    3. Observe the resulting waveform, which should resemble an 'eye' shape.

Step 5: Analyze the Eye Diagram

Finally, analyze the captured eye diagram to assess the quality of the signal.

  • Analysis Tips:
    1. Look for the opening of the eye; a wider opening indicates better signal integrity.
    2. Check for jitter and noise that could impact performance.
    3. Evaluate the vertical and horizontal eye heights; these indicate the signal's amplitude stability and timing.

Conclusion

Creating and analyzing an eye diagram is essential for understanding signal quality in digital communications. By following these steps, you can effectively visualize and evaluate the performance of digital signals. As a next step, consider experimenting with different signal types and settings on your oscilloscope to deepen your understanding of signal characteristics.