pulse detection circuit design

[lhlblue]

i want to generate a pulse as the figure shows, when the burst number of A is larger than 3 (N>=3), yhe output B is the same as A, but when N<3, output C is all zero.
i want to realize this as simply as possible.
what circuit should i use here?

 

[chuckey]

You have not stated your problem well. Lets see, when A = 0, B = ?, C = ?. when A burst < 4, B = ?, C = ?. when A burst >= 4, B = ?, C = ?. if you can fill in then ?, then I am sure some one might help you.
Frank

 

[lhlblue]

ok, when A = 0, B = 0 and C = 0; when N>=3, the output is the same as the input, when N<3, the output is zero. that is, if the input pulse is less than 3, i think it is a false trigger, if larger than 3, it is a real trigger.
thanks.

 

[crutschow]

How do you know when a burst is done? What is the time between bursts as compared to the burst frequency?