how to calculate phase difference for NI-9234 phase matching verification ?

[EricMgNiBh]

Hi

I am trying to verify phase matching for NI-9234 , I developed my program according to National instrument calibration procedure document but the phase value is keep changing as it must be,  and I could not find out how to calculate channel to channel phase difference. so I decided to monitor different channel in same program which error occures , does anyone have any idea about this problem ?

 NI said : "9. Calculate the phase for each channel on the NI 9234. NI recommends using the Extract Single Tone

Information VI to calculate phase.

10. Compare the channel-to-channel phase difference to the limits in Table 7."

[Henrik_Volkers]

Apply one sine signal to all channels, use only one task and configure a n-channel waveform read. for each waveform apply a extract single tone.vi and calc the phase difference eg. time delays.