Expalin johnson counter, Computer Engineering

Assignment Help:

Write short note on the Johnson counter.

Ans:

 Johnson Counter: It is a synchronous counter, where all flip-flops are clocked concurrently and the clock pulses drive the clock input of all the flip-flops together therefore there is no propagation delay. Fig.(a) demonstrates the circuit of Johnson counter. In case of the  D  input  of  FF0  is  driven  by  Q‾ output  of  FF3, that is, the complement of the output of the final flip flop is fed to the D of FF0. Feedback of this arrangement generates the sequence of states illustrated in Table no.1. The 4 bit sequence has a total of 8 states (there is n bit sequence will have 2n states). Therefore an n bit Johnson counter will have a modulus of 2n.

The Q output of all stage feeds the D input of next stage. Although the Q‾ output of the final stage feeds the D input of primary stage. The counter fills up along with 1's from left to right and after that fills up 0s again as demonstrated in Table no.2. Fig. (b) Demonstrates the wave shapes/timing diagram of 4 bit Johnson counter.

563_Logic Diagram of Johnson counter.png

Fig.(a) Logic Diagram of Johnson counter

Clock Pulse

Q0

Q1

Q2

Q3

0

0

0

0

0

1

1

0

0

0

2

1

1

0

0

3

1

1

1

0

4

1

1

1

1

5

0

1

1

1

6

0

0

1

1

7

0

0

0

1

Table no.1 Sequence of states of 4 bit Johnson Counter

2108_Timing Diagram of 4-bit Johnson Counter.png

Fig.(b) Timing Diagram of 4-bit Johnson Counter


Related Discussions:- Expalin johnson counter

Operations from events, Operations from events During analysis, events...

Operations from events During analysis, events which are sent to target objects. An operation on these object are presented as labels on transitions and should not be explicit

what are the advantages of threads over processes, What are the advantages...

What are the advantages of threads over processes? Some of the useful threads offer over processes includes: i)   It does not take more time to create and finished a new thr

What is pipelining, What is pipelining? The overlapping of implementati...

What is pipelining? The overlapping of implementation of successive instructions is known as pipelining.

Java Applet, Simple codes for robot using applet

Simple codes for robot using applet

Features of hyper-threading, The salient features of hyper threading are: ...

The salient features of hyper threading are: i)  Improved support for multi-threaded code, permitting multiple threads to run concurrently. ii) Response time and improved rea

What are stacks, What are stacks? A stack  is an abstract data type in...

What are stacks? A stack  is an abstract data type in which items are additional to and removed only from one end known as TOP. For example, consider the pile of papers on you

Advantages of e-commerce, One of the resources we used was Ajeet Khurana's ...

One of the resources we used was Ajeet Khurana's article that talks about the advantages of e-commerce. It was helpful to gain some background on the variety of benefits the electr

What is the different between index and subscript, Subscript refers to the ...

Subscript refers to the array of occurrence, whereas Index shown an occurrence of a table element. An index can only modified using perform, search & set. Require to have an index

Explain salient points about indirect addressing, Q. Explain salient points...

Q. Explain salient points about indirect addressing? A number of salient points about this scheme are:  In this addressing scheme effective address EA and contents of th

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd