A logic analyzer captures digital data from a digital system and presents it to a user so that the user can locate failure of the digital system.
A HP 1630D Logic Analyzer showing a timing diagram.The basic problem that a logic analyzer solves is that a digital circuit is too fast to be observed by a human being, and has too many channels to be examined with an oscilloscope.
A logic analyzer would trigger on a complicated sequence of digital events, and then copy a large amount of digital data from the system under test. The best logic analyzers behaved like software debuggers (showing the flow of the computer program), or oscilloscopes.
When logic analyzers first came into use, it was common to attach several hundred "clips" to a digital system. Later, specialized connectors came into use. In modern computer systems various other tools have made logic analyzers obsolete for many uses. For example, many microprocessors have hardware support for software debuggers. Many digital designs, including those of ICs, are simulated to detect defects before the unit is constructed. The simulation usually provides logic analysis displays. Often, complex discrete logic is verified by simulating inputs and testing outputs using boundary-scan logic. None of these exactly reproduce the high-speed data capture function of a logic analyzer, but they cover most real needs for debugging digital circuits