VXI SM8000 - Manual (Page 33)

VXI Technology, Inc.
SM8000 Series Operation 33
REGISTER
WRITE
BUSY
OUTPUT
300ms 16ms
F IGURE 3-8: M ULTI -S WITCH T IMING
Calculating Switching Time
The time-period for switching a channel can be divided into three constituent periods. The first
time-period ends when the BUSY signal goes high. For calculating switching time, however, only
the last two periods are used.
The second time-period starts when BUSY goes high and the switch armature begins to move.
There is a 16 ms period until the armature reaches the specified output channel. There is a 16 ms
period for each switched channel, including duplex and blocked channels. During this period,
optical output is invalid; optical noise may appear on various output channels as the armature
rotates.
The third time-period is called the debounce period. It ends when the armature is steady, the
switch has established a valid optical connection, and BUSY goes low. The debounce period lasts
for 300 ms.
Switching time is the sum of the second and third time-periods. For example:
Switch from Channel 15 to Channel 1 (1 x N Configuration)
Switches through 14 channels
(14 x 16 ms) + 300 ms = 524 ms
Switch from Channel 2 to Channel 6 (2 x N Blocking Configuration)
Switches through 2 x 4 (8) channels
(8 x 16 ms) + 300 ms = 428 ms