User Manual

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internal parts should reach safe temperature levels. In some circumstances (for example, when a fan is blocked
or damaged), the temperature may increase too much, and some internal components may break. In order to
avoid this unpleasant situation, a temperature alarm occurs when the temperature is over a maximum threshold
(75°C). This alarm triggers an immediate powering off of the output signal and an increase of the lockout
counter.
The power will be switched on again only when the temperature goes below a second threshold, lower than
the first (70°C).
z Forward and Reflected Powers
A forward or reflected power alarm occurs when the relevant monitored power level is over a threshold
(factory setting). Both alarms trigger an immediate powering off of the output signal and an increase of the
lockout counter.
You can see the levels of the power thresholds in the Amplifier menu (see the Menu Management paragraph).
z Power supply voltages (+5V, +12V, -12V)
Besides the amplifier power supply voltage (+28V), the ATSC TRANSMITTER uses three additional main
voltages: +5V, +12V, -12V. These voltages are continuously monitored by the control system and any variation
above 10% of the nominal value generates an alarm condition. This alarm does not trigger a powering off of
the output signal.
z No communication, Temperature and Generic modulator alarm
The ATSC Modulator module continuously communicates with the control system. If this communication fails,
the control board triggers a “No communication” alarm. This is a serious malfunction that must be solved as
soon as possible. In presence of a no communication alarm, the control system isn’t able to know the working
condition of the modulator (for example, the modulated output signal level), so it inhibits the power amplifier
stage and the output power is muted. uring normal working conditions, the internal temperature of the modulator
could increase above a safe threshold. In this case, the control system triggers a “Modulator over-temperature”
alarm and the output power is muted to let the temperature decrease.
As the modulator is a complex piece of hardware and software, other erroneous and/or dangerous conditions
could happen. In this cases, the control system triggers a generic “Modulator Error” alarm.
z External reference alarm
When external or ASI/SMPTE reference is set, the modulator continuously monitors the presence of such
reference. If it is not able to find a correct signal, it automatically switches to the internal reference. In this
situation, an external reference alarm is triggered. This alarm does not trigger a powering off event. See the
Synchronization and Clocks paragraph for more information.
z ASI/SMPTE inputs alarm
There are several conditions related to input streams that could trigger an alarm, depending on the working