29 votes 29 votes Advantage of synchronous sequential circuits over asynchronous ones is: faster operation ease of avoiding problems due to hazards lower hardware requirement better noise immunity none of the above Digital Logic gate1991 digital-logic normal sequential-circuit synchronous-asynchronous-circuits multiple-selects + – Kathleen asked Sep 12, 2014 • retagged Apr 17, 2021 by Lakshman Bhaiya Kathleen 8.6k views answer comment Share Follow See all 6 Comments See all 6 6 Comments reply Show 3 previous comments Itachi_Uchiha commented May 22, 2020 reply Follow Share Synchronous Counter are faster but more complex to implement, Asynchronous counter are slower but simpler to implement. 0 votes 0 votes Abhineet Singh commented Nov 11, 2020 reply Follow Share why is A not correct? synchronous counters are faster than asynchronous counter, cant we use this... 1 votes 1 votes neel19 commented Sep 3, 2022 reply Follow Share The transient pulse issues associated with hazards are rarely a problem in synchronous circuits. They are designed to allow sufficient time in each clock period for the glitches of both static and dynamic hazards to resolve.On the other hand, asynchronous logic circuits that can respond instantly to signal changes can be greatly affected. Link 0 votes 0 votes Please log in or register to add a comment.
Best answer 28 votes 28 votes Synchronization means less chance of hazards but can only increase the delay. So, synchronous circuits cannot have faster operation than asynchronous one but it is easier to avoid hazards in synchronous circuits. So, (A) is false and (B) is true. (C) is false if we don't consider how to avoid the hazards in asynchronous circuits. (D) Is not necessarily true - often asynchronous circuits have better noise immunity. Reasons are given here: http://www.cs.columbia.edu/~nowick/async-applications-PIEEE-99-berkel-josephs-nowick-published.pdf https://en.wikipedia.org/wiki/Asynchronous_circuit Arjun answered Dec 5, 2014 • edited Jun 16, 2018 by kenzou Arjun comment Share Follow See all 19 Comments See all 19 19 Comments reply Akash Kanase commented Nov 20, 2015 reply Follow Share In asynchronous circuits, local signaling eliminates the need for global synchronization which exploits some potential advantages in comparison with synchronous ones. They have shown potential specifications in low power consumption, design reuse, improved noise immunity and electromagnetic compatibility. Asynchronous circuits are more tolerant to process variations and external voltage fluctuations. Found this from wiki page you mentioned. Please give source for Point (d) 14 votes 14 votes shekhar chauhan commented Jun 11, 2016 reply Follow Share better noise immunity is not an advantage of synchronous sequential circuits Read this paper " Asynchronous circuits seem to be a good candidate to alleviate the problems originated by simultaneous switching noise. However, they are also more sensitive than synchronous ones to spurious signal transitions and delay variations produced by crosstalk noise ...." 3 votes 3 votes Bikram commented Oct 9, 2016 reply Follow Share option A is wrong , why so because ---> asynchronous circuits can be faster than synchronous circuits, ............." In asynchronous circuits, there is no clock, and the state of the circuit changes as soon as the input changes. Since they don't have to wait for a clock pulse to begin processing inputs, asynchronous circuits can be faster than synchronous circuits, and their speed is theoretically limited only by the propagation delays of the logic gates. so option a in this qs is wrong . and option B is True because --> If transitions on two inputs arrive at almost the same time, the circuit can go into the wrong state depending on slight differences in the propagation delays of the gates. This is called a race condition or hazard situation . In synchronous circuits this problem is " less severe" because race conditions can only occur due to inputs from outside the synchronous system .... see here https://en.wikipedia.org/wiki/Asynchronous_circuit#Synchronous_vs_asynchronous_logic 30 votes 30 votes sushmita commented Jan 14, 2017 reply Follow Share what about hardware requirement and noise immunity? 1 votes 1 votes Bikram commented Jan 14, 2017 reply Follow Share (c) is false if we don't consider how to avoid the hazards in asynchronous circuits. D) is also False , as better noise immunity is not an advantage of synchronous sequential circuits . Reference: [1] Click here 1 votes 1 votes shraddha_gami commented May 8, 2017 reply Follow Share @arjun sir Same question asked in isro 2017 But option B is not given Options given are A. Lower hardware requirement B. Better noise immunity C. Faster Operation D. All of the above So, may be more than one options are correct in this question and faster operation is also correct answer 0 votes 0 votes ManojK commented May 8, 2017 reply Follow Share I think No option is correct. 1 votes 1 votes yes commented May 8, 2017 reply Follow Share ....... 2 votes 2 votes Bikram commented May 9, 2017 reply Follow Share @yes The snap you posted have no relation with Asynchronous Circuit . "Most digital devices today use synchronous circuits. However asynchronous circuits have the potential to be faster, and may also have advantages in lower power consumption, lower electromagnetic interference, and better modularity in large systems." Read the first paragraph here -> https://en.wikipedia.org/wiki/Asynchronous_circuit Also search for this line too " Since asynchronous circuits don't have to wait for a clock pulse to begin processing inputs, they can be faster than synchronous circuits, and their speed is theoretically limited only by the propagation delays of the logic gates. " So combining all these is it not clear that Asynchronous circuit is faster than synchronous circuit ? 2 votes 2 votes Bikram commented May 26, 2017 reply Follow Share Option D " better noise immunity" is NOT TRUE/ Not a correct option This paper says "Asynchronous circuits seem to be a good candidate to alleviate ( means reduce ) the problems originated by simultaneous switching noise. However, they are also more sensitive than synchronous ones to spurious signal transitions .... " This line means asynchronous circuits are better to handle noise than synchronous circuits . So option D is not true here.. as question asked Advantage of synchronous sequential circuits over asynchronous one . 2 votes 2 votes Arjun commented May 26, 2017 reply Follow Share However, they are also more sensitive than synchronous ones to spurious signal transitions 0 votes 0 votes Bikram commented May 26, 2017 reply Follow Share yes Asynchronous circuits are more sensitive than synchronous ones , here more sensitive means Asynchronous circuits are quick to detect or respond to slight changes in signals than synchronous circuits. 1 votes 1 votes Bikram commented May 27, 2017 reply Follow Share Proof for option D is also False 1 votes 1 votes Arjun commented May 27, 2017 reply Follow Share @Bikram Yes, I was wrong -- corrected now. Also, this paper shows it. http://www.cs.columbia.edu/~nowick/async-applications-PIEEE-99-berkel-josephs-nowick-published.pdf 1 votes 1 votes rahul sharma 5 commented Sep 9, 2017 reply Follow Share @Arjun sir, Can you share some reference for Synchronization means less chance of hazards but can only increase the delay. ? 0 votes 0 votes sushmita commented Oct 23, 2017 reply Follow Share is false if we don't consider how to avoid the hazards in asynchronous circuits......... meaning?? I am not able to comprehend it. 0 votes 0 votes Raas Star commented Dec 17, 2019 reply Follow Share I think Synchronous-Circuit and Synchronous-flip-flop both are different things?? Plz correct me. 0 votes 0 votes nvs16 commented Aug 29, 2020 reply Follow Share Can anyone elaborate on option A. In case of asynchronous counters the first flip flop gets activated by clock only. So how is the speed comparison of sync and async counters? 1 votes 1 votes Abhrajyoti00 commented Jan 6, 2023 reply Follow Share Asynchronous circuits do not have a fixed clock, which can make them more susceptible to problems such as race conditions and indeterminate states. However, they may also have faster operation in some cases, since they are not limited by a clock frequency. 0 votes 0 votes Please log in or register to add a comment.
4 votes 4 votes Correct option is B, ease of avoiding problems due to hazards option B is True because --> If transitions on two inputs arrive at almost the same time, the circuit can go into the wrong state depending on slight differences in the propagation delays of the gates. This is called a race condition or hazard situation . In synchronous circuits this problem is " less severe" because race conditions can only occur due to inputs from outside the synchronous system .... see here https://en.wikipedia.org/wiki/Asynchronous_circuit#Synchronous_vs_asynchronous_logic And option A, C and D all are false... Bikram answered Aug 23, 2017 Bikram comment Share Follow See all 2 Comments See all 2 2 Comments reply rahul sharma 5 commented Sep 9, 2017 reply Follow Share @Bikram Sir. 1. You said that in asynchronous we dont have clock operation. But If i consider the case of counters.Now asynchronous counters are slower than synchronous counters as in asynchronous counters the clock is cascaded. 2. How synchronous will handle hazards easily?By hazards i am assuming static hazard.If i am not covering any adjacent group of minterms then hazards are possible. I think hazards are dependent upon the expresion that i am implementing in the circuit irrespective of synchronous or async ? 3 votes 3 votes nvs16 commented Aug 29, 2020 reply Follow Share I have the same doubt. Please clarify. @Arjun @Bikram sir 0 votes 0 votes Please log in or register to add a comment.