
AD9929
MSHUT High Precision Operation
The MSHUTPOS_HP register allows fine precision control of
the MSHUT position within a line. Under normal MSHUT
operation when MSHUTPOS_HP = 0, the MSHUT polarity
changes from high to low on the negative edge of the HD pulse,
as shown in Figure 53. By using the MSHUTPOS_HP register,
the rising and falling edges of MSHUT can be delayed by
multiples of the OL counter length that has been set in the
OLEN register. For example, if MSHUTPOS_HP = 3, the
Rev. A | Page 51 of 64
MSHUT rising and falling edges are delayed by three OL
counter cycles after the falling edge of HD, as shown in
Figure 56.
Figure 56 provides an example of high precision MSHUT and
SUBCK timing. In this example, the length of the OL counter is
shorter. This provides finer precision control of the placement
of the MSHUT pulse within a line.
VD
XSUBCK
t
EXP
XVSG1-
XVSG2
HD
MSHUTPOS = 3
MSHUTPAT = 0, MSHUTLEN = 5
MSHUT
OL
COUNTER
OL
COUNTER
OL
COUNTER
OL
COUNTER
1
2
3
1
2
3
4
5
0
Figure 59. Example of MSHUT High Precision Timing MSHUTEN = 1 and MSHUTPOS_HP = 3
XSUBCK
t
EXP
XVSG1-
XVSG2
MSHUTPOS = 3
MSHUTPAT = 0, MSHUTLEN = 5
MSHUT1
VD
HD
DELAY = 3 OL
COUNTER LENGTHS
MSHUT2
NOTES
1
MSHUT OUTPUT IN NORMAL OPERATION WITH MSHUTPOS_HP = 0
2
MSHUT OUTPUT IN HIGH PRECISION OPERATION WITH MSHUTPOS_HP = 3
Figure 60. Example of MSHUT High Precision Timing MSHUTEN = 1, MSHUTPOS_HP = 3, with XSUBCKMODE_HP = 1, XSUBCKNUM_HP = 3
0
1
2
3
1
2
3
4
5