Tektronix ECO 422, Instruction Manual

Page: 39 / 177

Operating Basics
ECO 422
2–7
State Machine Discussion
Table 2–2 is a truth table that gives the various states the ECO 422 outputs based
on the state of the inputs. Note that Primary is set to check a given level.
Power – the state of the power supply.
User Config – the state of the user configuration switch. It can either be N
(Normal) or O (Override). In Normal mode, the ECO 422 will not switch to a
“bad signal.” In Override operation, the user is allowed to manually switch to a
“bad signal.”
Switch – Indicates whether or not the Sync Source button on the front panel or
the Toggle Sync Source on the remote control has been selected. Note that the
front panel and the remote control commands are ANDed together (active low)
to produce the switch results.
P – Primary input. It outputs to Output.
B – Backup input. It is part of the Output set.
O Auto – Output signal with the ECO 422 set to “Auto Switching” (switch on
error). It can either output Primary or Backup.
O Manual – Output signal with the ECO 422 set to “Manual” (no switching on
error). It can either output Primary or Backup.
0 – bad signal.
1 – good signal.
"
– switch (change the current output signal).
#
– no switch (stay with the current signal).
X – Don’t care.