16
|
Why NAND gate SR
latch is called as active LOW SR latch?
|
|
The
output of the NAND gate SR latch is reverse of the NOR gate SR latch
therefore it is called as active LOW SR latch.
|
17
|
Why the gated S – R
latch is also called as level triggered flip – flops?
|
|
Gated
S – R latch
- The flip flops of the S – R latch
responds only when the clock is HIGH therefore it is also called as level
triggered flip – flops.
|
18
|
Which is invalid
condition for gated S – R latch?
|
|
S
= 1 and R = 1 for NAND gated S – R latch
S
= 0 and R = 0 for NOR gated S – R latch
|
19
|
How to obtain gated
D latch from gated SR latch?
|
|
The
SR latch consists of two inputs. The D latch is obtained from SR latch by
placing one inverter between S and R terminals. The D latch has only one input.
|
20
|
How many input the
gated D latch consists of?
|
|
As
the input S and R is complement to each other the gated D latch requires only
one input.
|
21
|
What do you mean by
word D in the D – latch?
|
|
The
word D in the D – latch is used for input data.
|
22
|
Why the gated D
latch is also called as transparent?
|
|
Gated
D latch
- The output of the gated D latch follows
the input when the ENABLE is high therefore it is called as transparent.
- When
the Enable is high, low D input makes output Q low. Similarly high D input
makes output Q high if the Enable is high.
|
23
|
When the gated D
latch becomes ineffective?
|
|
When
the ENABLE is low, the gated D latch becomes ineffective.
|
24
|
Describe the name of
different types of edge triggered flip flop.
|
|
Types
of edge triggered flip flop
- S – R flip flop
- J – K flip flop
- D flip flop
|
25
|
What is meaning of
the clocked flip flop?
|
|
Clocked
flip flop
- The flip flop using clock signal is
called as clocked flip flop.
|
26
|
Describe the
difference between asynchronous and synchronous digital system.
|
|
Asynchronous
- The output of the logic system can
change state when one or more input change.
Synchronous
- The output of the logic system can
change state which is determined by a clock signal.
|
27
|
Explain the term : Positive
edge triggered flip flop and negative edge triggered flip flop
|
|
Positive
edge triggered flip flop
- It is a flip flop in
which state transitions take place only at positive going of the clock pulse.
i.e. from Low to High
- It is represented by
triangular symbol.
Negative
edge triggered flip flop
- It is a flip flop in
which state transitions take place only at negative going of the clock pulse.
i.e. from High to Low
- It is represented by
triangular with bubble symbol.
|
28
|
Write the other name
of edge triggered flip flop.
|
|
Dynamic
triggered flip flop
|
29
|
Which type of
triggering indicates if there is no symbol at the clock input of the flip
flop?
|
|
Level
triggering
|
30
|
What are Synchronous
control inputs?
|
|
Synchronous
control inputs
- The S and R input of the S – R flip
flop is called as synchronous control inputs because the input affect the
flip flop’s output only during the positive edge of the clock pulse.
|
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