Asynchronous and synchronous logic design, Electrical Engineering

Assignment Help:

One of the simplest circuits is the asynchronous or ' ripple' counter. Below is shown the circuit diagram of a simple 3 stage ripple counter.

1234_Asynchronous and Synchronous logic design.png

The operation of this circuit is based on the fact that the truth table for the JK flip flop is only valid if the clock waveform is falling, i.e. 1->0. Assume the outputs are all zero, the flip flops will not change until the clock on each flip flop falls. The clock in waveform has just fallen  ,since the JKa inputs are logic '1' the device will toggle and the output will invert i.e. Qa=1. Flip flop B will not change because the clock waveform on B has risen    (0->1) and these devices only functions on a falling edge. The clock in waveform has fallen again, so Qa toggles again (i.e. Qa =0), this has just produced a falling clock on JKb and Qb toggles (i.e. Qab=1) .The device has just counted from 000-> 001->010.

960_Asynchronous and Synchronous logic design1.png

The circuit is called a ripple counter because the clock pulse is slowly rippling through the JK's, hence asynchronous (Not at the same time!) .The limitations of the asynchronous counter is the speed of operation. A rough formula for the maximum speed is when the clock changes before the output changes i.e.

      F =  1 / n x propagation delay
 
   where n = number of stages, propagation delay of one JK

A better technique is to use a synchronous design where all the JK are clocked together so the maximum frequency is only limited by the propagation delay of 1 JK.  

59_Asynchronous and Synchronous logic design2.png

 
The circuit appears to be complex in design, however it is easily realised by using state diagrams. The maximum frequency of operation is again roughly calculated by considering the frequency at which the output just changes before the clock in changes.
    
      F = 1/ Propagation delay


Related Discussions:- Asynchronous and synchronous logic design

Explain common emitter circuit, Q. Explain Common Emitter Circuit With The ...

Q. Explain Common Emitter Circuit With The Help Of A Circuit Diagram? Most transistor circuits have the emitter,rather than the base,as the terminalcommon to both input and out

Emirrer feedback bias, RE should be made large enough to swamp out rB/ B. h...

RE should be made large enough to swamp out rB/ B. how does making RE large saturate the transistor b

E. mechanics, a train weight 5 megaN is taking a slope of 1 in 200 at 45 km...

a train weight 5 megaN is taking a slope of 1 in 200 at 45 kmper hour.the engine put in 100 kw.determine the power to be put in by the engine it the train take the slope up of 1 in

Explain state-variable techniques, Q. Explain state-variable techniques? ...

Q. Explain state-variable techniques? The matrix formulations associated with state-variable techniques have largely replaced the block-diagram formulations. Computer software

Partial indicators method, Partial Indicators Method The partial indic...

Partial Indicators Method The partial indicators technique consists of calculating various measures of the financial, operating, commercial, and quality of a business's perfor

Show the r’s complement, Q. Show the r’s Complement? Step1- get the (r-...

Q. Show the r’s Complement? Step1- get the (r-1)'s complement Step 2- add 1 to the result ex.            935 10                                     9 9 9

What is non-folded network, Q. What is Non-Folded Network? Non-Folded ...

Q. What is Non-Folded Network? Non-Folded Network: In a switching network, all outlet/inlet connection may be used for inter exchange transmission. In such a case, exchange d

Lc circuits, L=0.0053nH, C=15µF find the operating frequency of series LC c...

L=0.0053nH, C=15µF find the operating frequency of series LC circuit. What factors decides capacitance ..

Inductive coupling, #question. i want design of inductive coupling to trans...

#question. i want design of inductive coupling to transfer power @ 2 watt in air gap of 5mm radial distance..

#titleclipper diode.., Ask quedisadvantages stion #Minimum 100 words accept...

Ask quedisadvantages stion #Minimum 100 words accepted#

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