analog output signal phase shifted?

[List]

I�m outputting a sinusoidal signal with a DAQ PCMCIA E-series device. I tray to figure out if there is a constant phase shift between the internally digital sine wave and the real externally generated analog signal or if the phase shift is rather random?
If I would, for example, drive a voltage controlled current source (1Hz�100Hz) and use an analog input channel of the same device to acquire the voltage drop across an impedance. Could I extract the phase information due to comparing the internally generated sine wave and the input signal?

[Chris Washington]

If I understand you correctly, you want to determine the phase shift between the output signal generated in software and the physical signal output from the device.

Because the time relationship between the signals is of interested, you will want to use hardware triggering or share the scan clock/update clock between the operations to ensure they start at the same time. I would also recommend a buffered (or at least hardware timed) acquisition.

Probably the simplest way will be to start the AI and AO at the same time with a hardware trigger and then compare the acquired signal to the signal generated in software. The AO buffer will match the signal in software and will start at the same time as the acquisition so you should be able to get reliable phase infor
mation in this way.

I hope his is helpful.

[List]

Thanks for your help!

I build up a VI and an external circuit and was able to get reliable phase information using buffered AI and AO.
I found out that there is a frequency depending phase shift between the output signal generated in software and the physical signal output from the device. (about 0.7 times frequency)
I would like to know where this phase shift comes from!? For help regarding this question I would be very grateful.

Regards Andreas