课程名称︰数位系统设计
课程性质︰必修
课程教师︰欧阳明
开课学院：电机资讯
开课系所︰资讯工程
考试日期（年月日）︰2010/1/13
考试时限（分钟）：180
是否需发放奖励金：是
（如未明确表示，则不予发放）
试题 :
1. (10%)
In your opinon, how to save the budget in recent digital system products
(consider the whole life cycle, from design to implementation) ? Please
provide at least two approaches to save the buget.
2. (20%)
(15%) (a) Design a 3-bit bidirectional counter, using only JK flip-flops.
(A bidirectional counter is that when state is 000 and x = 1, it should go
forward to state 001; when state is 000 and x = 0, it should go back to
state 111)
(5%) (b) Implement a T flip-flop only AND, OR, inverter gates, and RS
flip-flops.
3. (20%)
Design a circuit for calculating the answer of a binary input sequence with
modular 5 (mod 5) output, using only D flip-flops, (Hint : What is the state
diagram for calculating the answer of the input sequence for mod 3 ? For
example, 1101 mod 3 = 1. But this question is about mod 5, more complicated)
4. (20%)
There is a MN flip-flop, which
(1) if MN = 00, this flip-flop's next state is 0.
(2) if MN = 01, this flip-flop won't change its state.
(3) if MN = 10, this flip-flop's next state is the complement of present
state.
(4) if MN = 11, this flip-flop's next state is 1.
(a) Use present state (Q), next state (Q') and input (M, N) to
construct a table. (Notice : use don't care term as possible as
you can).
(b) Use derive table and K-Maps to design a counter which consists of
three MN flip-flops, and it's output sequence is as below:
ABC = 000, 010, 001, 100, 110, 000, 010, ...
(c) If your counter starts from unsigned state, what will happen ?
5. (5%)
In yout programming assignment (team work) for design or reverse
engineering, which part of your program is considered most time-consuming
when you designed your codes ? Based on the demos of your coding in order to
improve your results ?
6. (20%)
(10%) (a) Please find a minimum-state table that can replace the seven-state
table given below. Assume that A is the initial (reset) state.
(10%) (b) Just use the RS flip-flops to design the machine.
┌──────┬────────┐
│ │Present input x │
│ │ 0 1 │
├──────┼────────┤
│ A│ B,0 A,1 │
│ B│ C,1 D,0 │
│Prensent C│ E,1 C,1 │
│ state D│ A,1 D,0 │
│ E│ E,1 C,1 │
│ F│ F,0 G,1 │
│ G│ G,1 F,0 │
└──────┴────────┘
7. (5%)
When comparing the Mealy and Moore machines, which one or two are
asychronous ?
If it is asychronous, how to make it synchronous by simply modifying the
logic design slightly ?