Nautel NX100, Preinstallation Manual

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NX100 Pre-installation Manual Planning audio inputs
Issue 3.2 2017-03-31 Page 7-3
Other considerations
Frequency synchronization signals
You can apply a 10 MHz synchronization signal from an external source or using the optional GPS
sync PWB, which can be installed in the transmitter.
Optional GPS sync PWB
A GPS sync PWB can be purchased that is capable of driving a 3.3 V or 5 V GPS antenna. If the
optional GPS sync PWB is installed, it provides the necessary 10 MHz, 1 PPS and 1 kHz sync signals
used by the exciter(s). The exciter uses these signals to synchronize the transmitter to this GPS
reference. The GPS sync PWB connects to dual D-sub connector J5 of the control/interface PWB.
Externally sourced
If you are using an externally generated 10 MHz signal (such as a GPS clock signal) for use as the
reference frequency for the RF drive (carrier frequency), connect it to the
10 MHz SYNC
BNC
connector J8 on the control/interface PWB. The external 10 MHz frequency reference must:
– remain stable at 10 MHz within ± 20 Hz
– have a peak-to-peak amplitude of between 2.2 V and 8.0 V (sine wave or square wave)
– be spectrally pure, since spurs may pass through to the transmitter output.
Audio Player via USB
There is provision to configure the transmitter’s audio player feature to use an external USB device
connected to a USB port on the single-board computer (SBC). The files on the USB device (e.g., mp3
files) will act as the audio playlist. Refer to the
Operations and Maintenance Manual for details on using
the Audio Player’s Playlist feature, available through the AUI.
DRM Simulcast
For broadcasting in DRM simulcast, Nautel recommends applying the analog modultion input
directly to one of the transmitter’s audio inputs, in addition to the digital I/Q over AES stream being
applied to one of the transmitter’s AES inputs from the DRM modulator. This allows the transmitter
to effectively manage its own power control and protection, as it normally would.
NOTE
:
Do not connect the analog modulation source to a DRM modulator and apply a combined
analog and DRM signal to the transmitter. If the analog is combined with the DRM carriers by the
DRM modulator and applied to the transmitter as a single combined I/Q over AES stream, some of
the normal transmitter protections will not function properly.