Which statement about deterministic signals is true?

Which statement about deterministic signals is true?

• A. Given any time, the signal value can be determined exactly.
• B. The signal value is random and unpredictable.
• C. The signal repeats with unknown period.
• D. The signal is defined only over a finite interval.

Answer: (A)

Deterministic signals are those whose value at any time is fixed by a defining rule, with no randomness involved. In other words, once you know the rule and the time point, the value is exactly determined. That’s why the statement that, for any time, the signal value can be determined exactly with no ambiguity is the true description.

This contrasts with a random or unpredictable signal, where the value at a given time is not fixed and can vary in an unpredictable way. The idea of a signal being periodic with an unknown period isn’t the defining feature of determinism; a deterministic signal may be periodic or non-periodic—the key is that its value is fully determined by time. Finally, deteministic signals aren’t required to be defined only on a finite interval; they can be defined for all time, over a finite interval, or in piecewise fashion, as long as the rule that generates the values is fixed.