31
|
Describe the main
difference between JK flip flop and SR flip flop.
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|
JK
flip flop – SR flip flop
- The
JK flip flop has no invalid state that of in the SR flip flop.
- There is one
invalid state S = 1, R = 1 for NAND gated SR flip flop and S = 0, R = 0 for
NOR gated SR latch.
- When
J = 1 and K =1, the output toggles it means the output Q changes either 0 to
1 or 1 to 0.
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32
|
Why the output of
the JK flip flop toggles when input J = 1 and K = 1?
|
|
The
output Q and Q bar is feedback input K and input J respectively therefore the
output toggles when input J = 1 and K =1 in the JK flip flop.
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33
|
How to convert JK
flip flop into T flip flop?
|
|
The
JK flip flop is converted into T flip flop by connecting J and K input
together and labeled as T means toggle.
|
34
|
Which is the most
versatile flip flop?
|
|
JK
flip flop
|
35
|
When the T flip flop
toggles?
|
|
When
the input T is set 1 ( one ), the T flip flop toggles.
|
36
|
Describe the
function of asynchronous inputs? Which are the different asynchronous inputs.
|
|
Function
of Asynchronous Inputs
- The
asynchronous inputs can be used to SET the flip flop to state 1 or RESET the
flip flop 0 states without considering any input conditions.
- We
can say that the asynchronous inputs override the inputs. The asynchronous input
may be PRESET ( PRE ) or DC SET or direct set ( SD ) , DC CLEAR,
CLEAR or direct reset ( RD ).
|
37
|
Define : Propagation
delay time
|
|
Propagation
delay time
- It
is defined as the time interval between the time of triggering edge or
asynchronous inputs and the time at which the output makes transition.
- It
is given in the range of Micro second to Neno seconds.
- It
is measured between 50% points on the input and output waveform.
|
38
|
Define : Maximum
clock frequency
|
|
Maximum
clock frequency
- It
is defined as the highest frequency at which a flip flop can triggered
reliably.
|
39
|
Define : Set up time
|
|
Set
up time
- It
is defined as the minimum time for which the control levels needs to maintain
constant at the input terminal of the flip flop prior to the arrival of
triggering edge of clock pulse for reliable operation of the flip flop.
|
40
|
Define : Hold time
|
|
Hold
time
- It
is defined as the minimum time for which the control levels needs to maintain
constant at the input terminal of the flip flop after the arrival of
triggering edge of clock pulse for reliable operation of the flip flop.
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41
|
Explain the term
clock skew. Describe the effect of it.
|
|
Clock
skew
- When
a clock signal which is applied simultaneously to all flip flops in a
synchronous system, the delay of the signal to various flip flops are caused
by wiring between components and arrive of CLK inputs to flip flop at
different times.
- It is called as clock skew in the flip flop.
- If
the skew time is minimal, a flip flop may get clocked before narrow input
pulse arrives.
- Similarly
if the clock pulse is delayed, the input of the flip flop may have changed
before the clock pulse arrives.
- There
is race between two signals which is terms as time race.
|
42
|
State the holding
time of edge triggered flip flop.
|
|
The
holding time of edge triggered flip flop may be less than 5 Neno second.
|
43
|
Which flip flop has
no holding time?
|
|
Master
slave flip flop or Pulse triggered
flip flop
|
44
|
Why the master slave
flip flop is also called as Pulse triggered flip flop?
|
|
The
master slave flip flop is also called as pulse triggered flip flop because
the length of the time required for its output to change state equal to width
of one clock pulse.
|
45
|
How to avoid time
delay problem in the master slave flip flop?
|
|
Time
delay Problem
- The
time delay problem in the master slave flip flop is avoided by introducing a
known time delay between the time that the flip flop responds to clock pulse
and time the response appears at its output.
|
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