Q
EXC/EXC- waveforms are correct when resolver is disconnected, but have some
distortion once we connect the resolver. What do think could be the cause of
this distorsion?
A
From your schematic, I can see that the issue is caused by the wrong connection
of NPN transistor BC856. The emitter should be connected to 4.7ohm and
collector should be connected to gnd. Please refer to AD2S1210 evaluation board
schematic at:
http://www.analog.com/media/en/technical-documentation/evaluation-documentation/
EVAL-AD2S1210.pdf