Multiple choice

Two D flip-flops are connected as a synchronous counter that goes through the following QBQA sequence 00$\rightarrow$11$\rightarrow$01$\rightarrow$10$\rightarrow$00$\rightarrow$… The combination to the inputs DA and DB are

  1. DA = QB ; DB = QA

  2. DA = $\overline Q_A$; DB = $\overline Q_B$
  3. DA = $(Q_A \bar Q_B + \bar Q_A Q_B)$; DB = $\bar Q_A$
  4. DA = $(Q_A Q_B + \overline {Q_A Q_B})$; DB = $\overline Q_B$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation