Manual

71M6541 Demo Board REV 3.0 User’s Manual
39 Rev 4.0
5.
)cos(2
2
1800
S
XIXV
EE
AA
φ
++
=
6.
)cos(
12)(
1800
SXV
XI
A
EE
A
φ
++
=
Use above results along with E
60
and E
300
to calculate φ
S
.
7.
1
)60cos(
)60cos(
60
−
−
=
IV
AAIV
E
SXIXV
φ
1)sin()60tan()cos( −+=
SXIXVSXIXV
AAAA φφ
8.
1
)60cos(
)60cos(
300
−
−
−−
=
IV
AAIV
E
SXIXV
φ
1)sin()60tan()cos( −−=
SXIXVSXIXV
AAAA φφ
Subtract 8 from 7
9.
)sin()60tan(2
30060 SXIXV
AAEE
φ =−
use equation 5:
10.
)sin()60tan(
)cos(
2
1800
30060 S
S
EE
EE
φ
φ
++
=−
11.
)tan()60tan()2(
180030060 S
EEEE
φ ++=−
12.








++
−
=
−
)2)(60tan(
)(
tan
1800
30060
1
EE
EE
S
φ
Now that we know the A
XV
, A
XI
, and φ
S
errors, we calculate the new calibration voltage gain coefficient from the
previous ones:
XV
NEW
A
VCAL
VCAL
_
_ =
We calculate PHADJ from φ
S
, the desired phase lag:
[ ]
[ ]






−−−−
−−−+
=
−−
−−
)2cos()21(1)tan()2sin()21(
)2cos()21(2)21(1)tan(
2
0
9
0
9
0
929
20
TfTf
Tf
PHADJ
S
S
πφπ
πφ
And we calculate the new calibration current gain coefficient, including compensation for a slight gain increase
in the phase calibration circuit.
29
0
9
0
92020
)21()2cos()21(21
))2cos()21(222(2
1
1_
_
−−
−−−
−+−−
−−+
+
=
Tf
TfPHADJPHADJ
A
ICAL
ICAL
XI
NEW
π
π