Defined only at discrete values of time. The signal take one finite number of value at specific instant of time.

Defined as any physical or virtual quantity that varies with time or space, carrying information.

Defined for every value of time. The signal varies continuously in time and amplitude.

Defined as a physical or virtual quantity that varies with time or space or other variables.

If present output depends on the past or the future input

If the present output depends only on the present value of the input.

If the system not only depends on present and past inputs but also future input.

If the output of the system at any time depends only on present and past inputs.

If its input-output characteristics change with time.

If its input-output characteristics do not change with time.

If the system is one that does not satisfy the superposition principle.

If a system is one that satisfy the superposition principle.

A system whose output y[n] at time n depends only on the present and past input.

A system whose output y[n] at time n depends on any number of the past outputs values.

The system usually exhibits extreme behavior and cause overflow in any practical implementation.

If a bounded input to the system will produce bounded output – BIBO.

A process of mapping different ranking levels of amplitudes either a continuous or discrete signal to binary digital signal. (Convert continuous value to discrete value in vertical axis).

A process of measuring amplitude of a continuous time signal at a specific interval of time, T resulting in continuous to discrete signal conversion.

Non-Recursive. Since the present output is dependent only on inputs.

Recursive. Since the present output is dependent on its previous/past output.

without memory + causal

with memory + non-causal

without memory + non-causal

Linear only

Time-invariant + Linear