# asynchornous counter

Discussion in 'Homework Help' started by 5465da, Dec 28, 2012.

1. ### 5465da Thread Starter New Member

Dec 28, 2012
2
0
Question

1)In an asynchronous counter what is the frequency of the fifth flip flop when the clock input is 128khz?

Is it 4KHz?
since there is five flip flop divide by 2, five time?

2)A 3 bit johnson counter output is 800kHz, what is the input of it?
Is it 1.6MHz?
800kHz x 2 =1.6MHz ??????

I just wan to confirm with the answer

Last edited: Dec 28, 2012
2. ### WBahn Moderator

Mar 31, 2012
18,079
4,917
You answer to the first one is sound and so is your reasoning.

For the second one, describe the behavior of an n-bit Johnson counter. Is that consistent with your reasoning and answer?

3. ### 5465da Thread Starter New Member

Dec 28, 2012
2
0
second wan
2x3=6 since it is a johnson counter
Mod 6
Formula
Input= Mod x output
so 6 x 800khz = 4.8MHz Right????

4. ### WBahn Moderator

Mar 31, 2012
18,079
4,917
Correct (assuming that by "output frequency" they mean that the counter returns to the same state 800k times per second).

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