User's Manual

Screen Service SDT ARK 1 ECHO Operations
Jan, 2012 v 1.ATSC_FCC Page 3 - 29
3.4.3 Modes switching rules
Four switching rules are provided in order to cover different requirements:
 Manual: switch between mode A and mode B by selecting one mode using the Manual
Selector. The selected mode is always enabled until the user selects the other one.
 Auto: switch between mode A and mode B using the rules shown in the
following table. One mode is enabled until at least one of the alarms associated
to the enabled autoswitch rules is risen, then a countdown starts and, if the
parameter doesn’t regain a normal status during the timeout, the device
switches to the other mode.
Table 5. Autoswitch rules
Mode
Autoswitch rules
Heterodyne
Analog
repeater
No RF: No good Analog RF input. Video Carrier not locked. It is
associated to the No RF Input alarm.
Input Squelch: Received signal level under the squelch threshold. It is
associated to the RF Input Squelch alarm.
Heterodyne
Digital
repeater
No RF: video carrier not locked by the ATSC receiver. It is associated to
the No RF Input alarm.
Input Squelch: Received signal level under the squelch threshold. It is
associated to the RF Input Squelch alarm.
Tuner BER: Bit Error Rate after demodulator over the BER threshold. It
is associated to the RF Digital BER Alarm alarm.
Tuner S/N: Signal to Noise ratio under the S/N threshold. It is associated
to the S/N Level alarm.
TX ATSC
No RF: video carrier not locked by the ATSC receiver. It is associated to
the No RF Input alarm.
Input Squelch: Received signal level under the squelch threshold. It is
associated to the RF Input Squelch alarm.
Tuner BER: Bit Error Rate after demodulator over the BER threshold. It
is associated to the RF Digital BER Alarm alarm.
Tuner S/N: Signal to Noise ratio under the S/N threshold. It is associated
to the S/N Level alarm.
No TS Input: selected TS input not locked. TS input Alarm should be
enabled in the RF Off alarms mask. It is associated to the ATSC No Input
alarm.
 Opto: switch between mode A and mode B by selecting one mode using the
Opto 1 input with the following rules:
o 1 – Open: Mode A.
o 0 – Closed: Mode B.
 Time: switch between mode A and mode B at the specified Date and Time. Switching
will happen only one time from A to B. In order to set the Switching Time, select hours,
minutes, seconds, days, months and years, and click on up/down arrows to
increase/decrease them.