Programmable Logic Device MCQs

Question 1

A modulus-10 counter must have ________.

Accepted Answer

flip-flops

Answer

10 flip-flops

Answer

2 flip-flops

Answer

synchronous clocking

Question 2

For a one-shot application, how can HDL code be used to make a circuit respond once to each positive transition on its trigger input?

Accepted Answer

By using edge trapping

Answer

By using a counter

Answer

By using an active clock

Answer

By using an immediate reload

Question 3

Which is not an example of a truncated modulus?

Accepted Answer

8

Answer

9

Answer

11

Answer

15

Question 4

Four cascaded modulus-10 counters have an overall modulus of ________.

Accepted Answer

10,000

Answer

10

Answer

100

Answer

1,000

Question 5

What is the maximum delay that can occur if four flip-flops are connected as a ripple counter and each flip-flop has propagation delays of tPHL = 22 ns and tPLH = 15 ns?

Accepted Answer

88 ns

Answer

15 ns

Answer

22 ns

Answer

60 ns

Question 6

Which of the following statements are true?

Accepted Answer

Asynchronous events do not occur at the same time.

Answer

Asynchronous events are controlled by a clock.

Answer

Synchronous events do not need a clock to control them.

Answer

Only asynchronous events need a control clock.

Question 7

Which segments (by letter) of a seven-segment display need to be active in order to display a digit 6?

Accepted Answer

a, c, d, e, f, and g

Answer

b, c, d, e, f, and g

Answer

a, b, c, d, and f

Answer

b, c, d, e, and f

Question 8

Which of the following groups of logic devices would be the minimum required for a MOD-64 synchronous counter?

Accepted Answer

Six flip-flops, four AND gates

Answer

Five flip-flops, three AND gates

Answer

Seven flip-flops, five AND gates

Answer

Four flip-flops, ten AND gates

Question 9

A 22-MHz clock signal is put into a MOD-16 counter. What is the frequency of the Q output of each stage of the counter?

Accepted Answer

Q1 = 11 MHz, Q2 = 5.5 MHz, Q3 = 2.75 MHz, Q4 = 1.375 MHz

Answer

Q1 = 22 MHz, Q2 = 11 MHz, Q3 = 5.5 MHz, Q4 = 2.75 MHz

Answer

Q1 = 11 MHz, Q2 = 11 MHz, Q3 = 11 MHz, Q4 = 11 MHz

Answer

Q1 = 22 MHz, Q2 = 22 MHz, Q3 = 22 MHz, Q4 = 22 MHz