Satya Prakash Singh

I'm generating 1V(p-p) on W1 and 500mV(p-p) on W2 with zero phase on both the channels with my Analog Discovery 2 board. Initially it is showing a phase difference of about 30degs . Then, every time I stop and rerun the waveform channels the phase between W1 and W2 is not stable. What is the reason for this and what are the possible solution for this problem? Thanks Satya Prakash Singh