Specifications

5/9/13 888-2857-001 xv
WARNING: Disconnect primary power prior to servicing.
An optional circuit card for the modulator section of the low power unit (LPU). It
provides the necessary interface to allow the modulator to accept ETI transport
streams according to the DAB digital transmission standard.
Ethernet:
The physical interface by which the VAX transmitter may be connected to a LAN
and/or the Internet to provide web-based supervision. It generally employs an RJ45
connector.
EVM (Error Vector Magnitude):
A measure used to quantify the performance of the quality the digital being
transmitted. A signal sent by an ideal transmitter would have all constellation points
precisely at the ideal locations. However, various imperfections in the signal path
cause the actual constellation points to deviate from the ideal locations by finite
error vectors. Generally associated with the ATSC modulation standard. Analogous
to the modulation error ration (MER) used for the DVB, DAB and other modulation
standards.
FPGA (Field Programmable Gate Array):
An integrated circuit designed to be configured by the customer or designer after
manufacturing. FPGAs perform many of the intensive digital processing steps used
to synthesize the transmitted RF signal in the LPU modulator section.
GPS (Global Positioning System):
A satellite-based navigation system commonly used for determining position and
navigating. In a single frequency network context, it delivers an extremely precise
time reference (UTC... universal time, coordinated) used to synchronize all
transmitters.
Guard Interval:
A time interval at the start of each transmitted symbol in a digital COFDM system.
Distortions to the received signal due to time-delayed reflections or interfering
transmitters falling in this interval are ignored by the receiver.
GUI (Graphical User Interface):
A type of user interface that allows users to interact with electronic devices via
images rather than text commands. In this application, the user interface provided
by the TCU touch screen in dual drive systems or the web-based remote interface
served over the Ethernet interface.