Which counter encounters propagation delay?

Which counter encounters propagation delay?

Propagation delay refers to the amount of time taken in producing an output when the input is altered. Explanation: Since a counter is constructed using flip-flops, therefore, the propagation delay in the counter occurs only due to the flip-flops. Each bit has propagation delay = 12ns.

Which type of counter does not have a propagation delay?

Synchronous Counter Summary
Synchronous Counter Summary are all clocked together at the same time with the same clock signal. Due to this common clock pulse all output states switch or change simultaneously. With all clock inputs wired together there is no inherent propagation delay.

What are the limitations of asynchronous counter?

Disadvantages of Asynchronous Counters:

• An extra “re-synchronizing” output flip-flop may be required.
• To count a truncated sequence not equal to 2n, extra feedback logic is required.
• Counting a large number of bits, propagation delay by successive stages may become undesirably large.

What are the advantages and disadvantages of synchronous and asynchronous counters?

Advantages / Disadvantages of Synchronous Counters

• Very easy to design this circuit because we may set the same clock pulse for all gates.
• Less likely to end up in erroneous states.
• They are faster as the the propagation delay are small as compared to asynchronous counters.

What are the advantages and disadvantages of synchronous over asynchronous counter?

Count sequence is controlled using logic gates, error chances are lower. Faster operation than the Asynchronous counter. All flip flops in synchronous counter are driven by a single, common clock pulse. They require large components and circuitry than asynchronous counters.

What is diff between synchronous and asynchronous?

Synchronous = happens at the same time. Asynchronous = doesn’t happen at the same time. With synchronous learning, participants can receive immediate feedback. With asynchronous learning, the participants can learn at their own pace.

Why are asynchronous counters used as frequency dividers?

While counting large number of bits, the propagation delay of asynchronous counters is very large. For high clock frequencies, counting errors may occur, due to propagation delay. Asynchronous counters are used as frequency dividers, as divide by N counters.

Why is there no delay in an asynchronous counter?

If it is just a ‘pre-scaler’ used to divide a fixed high frequency to a lower frequency and it runs continuously then there is no delay issue. In a way the count of any one stage is unknown and has a “don’t care” policy. The problem with asynchronous counter is the “ripple”.

Why is MOD not equal to 2n in asynchronous counters?

To count the sequence of truncated counters (mod is not equal to 2n), we need additional feedback logic. While counting large number of bits, the propagation delay of asynchronous counters is very large. For high clock frequencies, counting errors may occur, due to propagation delay.

What is the minimum propagation delay between clocks?

Therefore the minimum acceptable time between clocks is 8ns + JK setup time. So long as this timing is met the counter should work correctly, and the propagation delay will be 2ns because Q outputs only change in response to clock inputs. Thanks for contributing an answer to Electrical Engineering Stack Exchange!