Hello Pavan,
I looked at the AI code you had posted previously and it looks like you
are reading in the signal at 10MHz and then generating at 4MHz.
If this is the case, you should see a decrease of the generated
frequency because you are acquiring 2.5 times as many samples per
second as you are generating. Double check your code and make
sure that you really are both acquiring and generating at the same
rate. If you are you should be generating the signal at the same
frequency.
Regards,
Micaela N
National Instruments