external clock source(unequal frequency) problem

Hello, l have sampling problem which is using an unequal frequency clock source.

I made a vi that convert analog signal to digital signal. so I can use that digital signal for clock source.

If analog signal has an unequal frequency, the clock source will have same unequal frequency.   

So, using that unequal(variant) frequency source for sampling, the data could not have a equal dt (sampling)point.

but the result was data has a equal dt point. which is it doesn't work as real time sampling(single shot sampling).

I want real time sampling. can you tell me how? 

need help.

Thank you.