User's Manual

Digital ATSC Exciter-Modulator System Chapter 2,
Installation and Operating Instructions
Axcera Axciter, Rev. 0 7
4. There is a SPDT RF relay, mounted in the upconverter/ downconverter
tray, in a tray-based system or externally in a sled-based system,
which selects an RF sample from one of two places. The samples are
from either before the transmitter output channel mask filter, Non-
Linear Distortion, or after it, Linear Distortion. These samples are used
in the adaptive equalization process. Connect one 50O coax cable from
the directional coupler installed before the channel mask filter to the
normally open position of the RF relay at J17 on the rear of the
upconverter tray or to J1 on the external relay. Connect another 50O
coax cable from the directional coupler installed after the channel filter
to the normally closed input on the RF relay at J16 on the rear of the
upconverter tray or to J2 on the external relay. In a tray-based
system, connect a 50O coaxial jumper cable from the common
connection of the relay at J24 to the sample RF input jack at J4 on the
rear of the upconverter tray. In a sled-based system, connect a 50O
coaxial jumper cable from the common connection of the external relay
at J3 to the downconverter sample RF input jack at J41 on the rear of
the driver/amplifier assembly. The relay, mounted in the upconverter
or external, will select between the two samples under software control
from the Axciter Modulator tray.
5. Optional connections. There are several optional connections, detailed
in table 2-4. An external 10 MHz reference input can connect to J9.
An active loop-thru (that is, regenerated and reclocked) SMPTE 310
signal is available at the SMPTE 310 output located on the rear panel.
6. Ethernet connection. J1 on the rear of the Axciter modulator provides
an Ethernet connection that is used for troubleshooting.
Axciter Modulator, Upconverter/Downconverter & Driver/Amplifier Rear Panels
Figure 2-4: Axciter Modulator Tray, Rear View
Figure 2-5: Upconverter/Downconverter Tray, Rear View
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Select
Switch
On/Off
Circuit
Breaker
On/Off
Circuit
Breaker