GUIDE TO INSTALLATION AND OPERATION
18
| XVP-1801
To determine the limits of a clean switch region, you must know the input’s line length in
μ
s. The first region
is delimited by +½ line and -½ line of the reference. For example, with an SD (525) signal the line length is
63.5
μ
s and so the first region lies between -31.76
μ
s and 31.76
μ
s. Other regions can be found by adding or
removing a multiple of line length to the two boundaries.
Example: for an SD (525) input signal, we have these clean switch regions:
-1 line and -31.76
μ
s to 0 line and -31.76
μ
s
0 line and -31.76
μ
s to 0 line and 31.76
μ
s
0 line and 31.76
μ
s to 1 line and 31.76
μ
s
etc.
Practical examples:
Example 1:
we have two SD (525) sources, one that indicates an offset of -25
μ
s with respect to the
reference (A) and the other an offset of -35
μ
s (B). We know that a clean switch region limit is present at -½
line, which corresponds to -31.76
μ
s. We can now determine that this switch will not be clean, because the
two sources are on opposite sides of the limit, and are therefore not in the same clean switch region.
Example 2:
We have two SD (525) sources, one that indicates an offset of 50
μ
s with respect to the reference
(A) and the other an offset of 40
μ
s (B). We know that a clean switch region limit is present at + ½ line and
another one at ½ line plus one line. These correspond to 31.76
μ
s and 95.28
μ
s. We can now determine that
this switch will be clean, because the two sources are inside the same clean switch region.