The eye diagram is created by superimposing multiple signal waveforms taken at the receiver over time, with the vertical axis representing the amplitude of the signal and the horizontal axis representing time. The resulting plot forms the shape of an "eye," with the size and shape of the eye indicating the quality of the signal. A wide, well-formed eye with clear edges indicates a high-quality signal, and a narrow, distorted eye with fuzzy edges indicates a poor-quality signal. Eye diagrams are easily created in the laboratory or as part of a system simulation. The impact of the pulse shape, timing errors (clock jitter), and noise can be observed from eye diagrams. This Demonstration shows the synchronized superposition of seven raised cosine pulses. You can adjust the Nyquist bandwidth, roll-off factor, percentage of clock jitter and energy per bit to noise power spectral density ratio in dB) and see the resulting impact on the eye diagram.