Which of the following statements are true regarding the eye diagram in the communication system?

a) An eye diagram is used to investigate Intersymbol interference.

b) The width of the eye-opening indicates an interval where the wave can be sampled without ISI.

c) Eye diagram is observed in Digital storage oscilloscope.

Explanation:

Eye Diagram in Communication Systems

The eye diagram is a powerful tool used in digital communication systems to evaluate the quality of a signal and diagnose issues such as inter-symbol interference (ISI). It is named for its characteristic shape, which resembles the human eye when viewed on an oscilloscope. The eye diagram is created by superimposing multiple traces of the signal waveform over a single period, allowing for the visualization of the signal's behavior over time.

Let us analyze the statements provided and understand why option 2 (a, b, and c) is the correct answer.

Statement a: An eye diagram is used to investigate inter-symbol interference.

This statement is true. The eye diagram is an essential tool for identifying and evaluating inter-symbol interference (ISI). ISI occurs when previous symbols interfere with the current symbol, leading to distortion and potential errors in the received signal. By examining the eye diagram, engineers can observe the effects of ISI, as it will cause the eye opening to close, indicating increased potential for symbol errors.

Statement b: The width of the eye-opening indicates an interval where the wave can be sampled without ISI.

This statement is also true. The eye opening's width is a critical feature of the eye diagram, representing the time interval during which the signal can be reliably sampled without the influence of ISI. A wider eye opening indicates a more robust signal with less ISI, allowing for more accurate sampling and decoding of the transmitted data. Conversely, a narrower eye opening suggests higher levels of ISI and a greater likelihood of errors.

Statement c: Eye diagram is observed in Digital storage oscilloscope.

This statement is true as well. Eye diagrams are typically observed using a digital storage oscilloscope (DSO). A DSO captures and stores the signal waveforms, allowing for the superposition of multiple periods to create the eye diagram. The DSO provides the necessary resolution and bandwidth to accurately display the high-speed digital signals used in modern communication systems.