# Which among the following assertions represents a necessary condition for the existence of Fourier Transform of discrete time signal (DTFT)?

A. Discrete Time Signal should be absolutely summable

B. Discrete Time Signal should be absolutely multipliable

C. Discrete Time Signal should be absolutely integrable

D. Discrete Time Signal should be absolutely differentiable

A. Replication

B. Sampling

C. Scaling

D. Product

A. a > 1

B. 0 < a < 1

C. a < -1

D. -1 < a < 0

A. sinusoid signals multiplied by growing exponentials

B. sinusoid signals divided by growing exponentials

C. sinusoid signals multiplied by decaying exponentials

D. sinusoid signals divided by decaying exponentials

A. Decreases with an increase in the magnitude of an independent variable (x)

B. Increases with an increase in the magnitude of an independent variable (x)

C. Always remains constant irrespective of variation in magnitude of 'x'

D. Cannot be defined

**A system is said to be shift invariant only if______**

A. a shift in the input signal also results in the corresponding shift in the output

B. a shift in the input signal does not exhibit the corresponding shift in the output

C. a shifting level does not vary in an input as well as output

D. a shifting at input does not affect the output