Hi, 
         
            I am trying to find phase difference between two acquired signals. In this project I varies frequency of input voltage continuously using for loop and measure two output voltages corresponds to each frequency from my circuit. I need to find the phase difference between two voltages accurately. Here I used "frequency amplitude" vi.. but each time when I execute the program with same circuit for particular frequency, phase difference changes... Is there any other method suitable for this project to calculate phase difference... I attached my vi along with this post. 
  
  
                                             Thanking you, 
                                                    Manu 
phase.vi