Purists may argue that you can't create true eye diagrams by using the eye-scan mode of Agilent's new 68-channel, 300/600-MHz (state), 1.2-GHz (timing)/4-GHz (timing-zoom), deep-memory logic-analysis ...

Here is a simple logic state indicator to test whether the output of digital IC is in logic 1 or 0. The Bicolor LED lights Green when the logic state is 1. ... Logic Stage Indicator Circuit Diagram.