Kontrollküsimused 3. osa kohta – Signaalitöötluse põhivara

According to Euler formula equals to ...

A discrete time signal is shown on the figure below. What is the formula of the signal?

u[2-n]-u[n-4]

u[4]-u[2]

u[n+2]-u[n-4]

u[n-2]-u[n+4]

Consider these signals:

1.

--------------------------------------------------------

2.

--------------------------------------------------------

3.

--------------------------------------------------------

4.

--------------------------------------------------------

5.

Match the equations with the corresponding signals!

Signal #1	delta[n-3] Unselect e^wt Unselect cos(t) Unselect e^jwt Unselect u[n+2] Unselect
Signal #2	delta[n-3] Unselect e^wt Unselect cos(t) Unselect e^jwt Unselect u[n+2] Unselect
Signal #3	delta[n-3] Unselect e^wt Unselect cos(t) Unselect e^jwt Unselect u[n+2] Unselect
Signal #4	delta[n-3] Unselect e^wt Unselect cos(t) Unselect e^jwt Unselect u[n+2] Unselect
Signal #5	delta[n-3] Unselect e^wt Unselect cos(t) Unselect e^jwt Unselect u[n+2] Unselect

Is the sum of two periodic signals also always periodic?

True

False

Which signal is shown on the figure?

2*cos(t-Pi/2)

2*sin(2*t+Pi/2)

sin(2*t-Pi/2)

cos(2*t-Pi/2)

2*cos(t+Pi/2)

A system is described with y(t)=x(t)*cos(w*t), where x(t) is the input of the system. Is the system linear?

True

False

Which of the following signals are periodic?