## Viva Questions on Systems

Viva Questions on Systems, Short Questions on Systems, Continuous-Time System, Discrete-Time System, Engineering Viva Questions, Signal & Systems Viva Questions, Short Questions on Signal & Systems,

### Short Questions and Answers

**Q.1.** *Define system.*

**Ans.** A system is defined as a physical device that generates a response, or output signal, for a given input signal.

**Q.2.** *Define (i) Continuous-time system (ii) Discrete-time system.*

**Ans.**

** Continuous-Time System:** A continuous-time system is one that operates on a continuous-time input signal and produces a continuous-time output signal.

** Discrete-Time System:** A discrete-time system is one that operates on discrete-time input signals and produces a discrete-time input signal.

**Q.3.** *What is the classification of the system?*

**Ans.**

- Static and dynamic systems.
- Time-variant and time-invariant systems.
- Linear and non-linear systems.
- Stable and unstable systems.
- Causal and non-causal system.

**Q.4.** *Define linear-time invariant system.*

**Ans.** An LTI system is one that possesses two basic properties, linearity and time-invariance.

** Linearity:** An LTI system obeys the superposition principle which states that the output of the system to a weighted sum of inputs is equal to the weighted sum of the outputs corresponding to each of the individual inputs.

** Time invariance:** If the input-output relation of a system does not vary with time, then the system is said to be time-invariant

**Q.5.** *Is the system y(t) = y(t – 1) + 2t y(t – 2) time-invariant?*

**Ans.** No. The system is time-variant. The coefficient 2t of the difference equation is a function of time.

**Q.6.** *Define static and dynamic systems.*

**Ans.**

** Static system:** A static or memoryless system is a system whose output at any instant depends only on the input value at that instant.

** Dynamic system:** A dynamic is one in which the output at any instant depends on past or future values of inputs.

**Q.7.** *Define a causal system.*

**Ans.** A system is said to be causal if the output of the system at any time depends only on the present and past inputs, but does not depend on future inputs.

**Q.8.** *What is a stable system?*

**Ans.** Any relaxed system is said to be bounded input-bounded output (BIRO) stable if and only if every bounded input yields a bounded output.