The Boolean expression of the circuit given in the figure is

Identify the logic operation performed by the given circuit.

Given below are four logic gate symbols (figure). Those for $OR$,$NOR$ and $NAND$ are respectively:

To get the truth table shown from the following logic circuit, the gate $G$ should be

Digital signals are characterized by which of the following statements?
$(i)$ They do not provide continuous values.
$(ii)$ They represent values in discrete steps.
$(iii)$ They can be represented by a binary system.
$(iv)$ They represent both binary and decimal systems.

The following diagram performs the logic function of: