phase measurement

Hi, 

Attached is the model I built for phase measurement.

Since the samp_rate (5M) is 8 times of signal source freq (625k),  the phase should be expected as shown in the table, while the measured phase is only correct when there is half cycle or full cycle delay. 

What can I do to make it correct?

Delay step	Expected phase delay	Measured phase delay
0	0	0
1	-0.79	-1.5
2	-1.57	-4.7
3	-2.36	-1.5
4	-3.14	-3.14
5	-3.93	-1.57
6	-4.71	-1.57
7	-5.5	-1.57
8	0	0

Thank you and best regards

Karen