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DIGITAL FUNDAMENTALS
11/17/2015
Q1. Option d/ base 3
Q2. Option b/ any logic function can be realized by NAND gates alone
Q3. Option a/ floating point hardware is costly
Q4. Option d/ logic 0 voltage level is lower than logic 1 voltage level
Q5. Option c/ECL
Q6. Option d/ S and R are connected to Q and Q' respectively
Q7. Option a/ Set of capacitor used to register input instructions in a digital computer
Q8. Option c/ R S type flip-flop
Q9. Option a/ It allows the use of cheaper analog techniques, which are always simpler
Q10. Option d/all inputs are HIGH
Q11.
a. Minterm and maxterm
Boolean function of variables is the most extra ordinary function, a when each variable
can be appears at single time, it is called Minterm
Minterm has single 1 and remaining all are 0s. In the Karnaugh Map it has been
identified properly.
F= (X+X’ .Y)
F= X.1+ X’Y
= X (1+Y) + X’Y
= X+Y (X+X’)
= X+Y.1
= X+Y (ans)
Q12.
a.
INPUTS
A
B
0
0
0
0
0
1
0
1
1
0
1
0
1
1
1
1
OUTPUTS
CIN
COUT S
0
0
0
1
0
1
0
0
1
1
1
0
0
0
1
1
1
0
0
1
0
1
1
1
After that put a inverter circuit
INPUTS
A
B
0
0
0
1
OUTPUTS
CIN
COUT S
1
1
0
1
0
1
1
1
0
1
1
1
1
1
1
0
Q13.
a. High level triggering: it can be identified when HIGH state of respond is
needed. This is about straight lead from clock input.
High
clock
level
Q
CLK
Q’
Low Level triggering: it can be identified when LOW state of respond is needed. This
is about low straight indicator lead from clock input.
Low
clock
level
Q
CLK
Q’
Positive Edge triggering: The Flip Flop is required to be in LOW and HIGH both
transition state then positive edge methods is basically used.
High
clock
level
Q
CLK
Q’
b. T Filp Flop:
In this picture it has been identified that T toggle flip flop changes its basic
output which is exactly half way of frequency of the signal to the T input. This is
used because to handle the binary counter, addition and frequency dividers.
The T flip flop is mostly used and it created from J-K Flip flop by effective high
inputs.
Q
T
Q’
Q14.
a. Shift Register: In the digital circuits, register should be needed anywhere because it can
share the same clock. A shift Register is mainly a cascade of the Flip Flops, by which out of
each and every flip flop should be connected to the ‘data’. Shifting the position of the input
to the next bit array that’s why it is called Shift register
b. Multiplexer: ‘MUX’- is the short name of the multiplexer, which is basically a device which
selects one of the as many as possible analog or kind of digital signals and forward to
selected input signal line.
Q15.
a. Four Bit Ring Counter:
Feedback Loop
D
Qa
Q
CLK
CLR
1
Qb
D
Q
CLK
CLR
0
Qc
D
Q
CLK
CLR
CLR
0
Qd
D
CLK
CLR
Q
1
b. Differences between combinational and sequential circuit
SL No.
Combinational circuit
Sequential circuit
1.
No memory element it contains
Contents memory elements
2.
Present value of outputs are basically
solely determined as by the present value
of inputs
Present value of outputs are totally
determined as by the present value of
inputs and also past state
3.
Behavior depends upon the set of output
function
Depends upon the next state or the
memory