generate a sinewave and acquire it at the same time to measure impedance

[64 Newman Street]

hi

 i want to measure the impedance , and i want to generate and acquire signal simultaneously to calculate the impedance. its important for me that the two generat&acquire signals will be simultaneously. i have capacitor in my circuit and to measure its size i need to be sure that the two signal begin at the same time. ive read the sample examples of labview carefully , but i still have problam since the two signal dont begin same time. i want to ask if someone please help me . i send my program too. i use labVIEW example, just change some parts

tanx in advance

[Toader Mihai]

Hello,

I think a simple solution to the problem is to wire an extra analog input at the circuit input and sample both of them with the same sample clock, as such you will now have exactly the signal you are suppling to the circuit:

AO -------------------------|  |---------------AI0

                         |-----------------------AI1

Then compare AI0 and AI1 and this should be your raw data.

Regards,

Toader Mihai

[64 Newman Street]

thanks for ur response , but I have tried this way ,too! and it didnt answer. I have my problam that is having some phase shift remained.

Is there any way to make sure that both signal generation and acqusiation start at the same time?

i have to mention that I use a USB X-series

Thanks again