BIBO stability stands for and means what?

• A. Bounded-Input, Bounded-Output; bounded inputs yield bounded outputs
• B. Binary Input, Binary Output
• C. Bifurcation Input, Bounded Output
• D. Basic Input, Basic Output

Answer: (A)

BIBO stability is about how a system behaves when the input is limited in magnitude. If every input signal that is bounded in size produces an output that stays bounded in size, the system is BIBO stable. This is the precise way engineers express the idea of stability for many signal processing and control systems: bounded inputs should not cause unbounded outputs.

The acronym itself reflects this: Bounded-Input, Bounded-Output. If the input is bounded, the output must also be bounded. In practical terms, for continuous-time linear time-invariant systems, this stability occurs when the impulse response is absolutely integrable; for discrete-time systems, the impulse response must be absolutely summable. The other options don’t describe this stability idea—they reference binary signals or nonstandard terms, which don’t capture the standard meaning of BIBO stability.