User Manual Part 2

Theory of Operation 8-2MTX5000 User and Technical Manual
A digital attenuator in the ODU RF chain allows you to transmit at
high or low power or to increment the power in single dB steps
for advanced fine tuning.
Inside the IDU, a control processor is responsible for configuring
the various sub-systems within the radio. The main processor
stores radio information in selectable presets that can be
recalled by the user.
The MTX5000 employs an advanced MPEG video encoder and
digital modulator. The MTX5000 includes the FMT modulator,
COFDM modulator and MPEG encoder, DC power supply, and
signal control and distribution boards, depending upon the
options contained in your MTX5000. A typical functional block
diagram of the MTX5000 is shown in Figure 8-1 on page 8-4.
8.2.3 MPEG Encoding and COFDM Transmission
The MTX5000 is capable of encoding both Standard Definition
and High Definition video (depending on license). Available
inputs include SD Serialized Digital Interface video (SD-SDI),
HD-SDI, and Composite Video (CV). Audio input formats include
analog, AES/EBU, and AC-3 SMPTE-302. The encoder is also
capable of encoding an RS-232 signal as Wayside data.
The MTX5000 is capable of generating a fully DVB-T compliant
output signal. This provides a robust digital link in any hostile
transmission environment.
8.2.4 Analog Video Encoding and FM Modulation
When in the analog FM mode, the MTX5000 will accept a
standard composite video input. It will also accept up to four
analog audio inputs. The FM analog signal is useful when
working with older legacy equipment or when an analog
transmission is desired.
8.2.5 MTX5000 User Interface
Local Mode Operation The MTX5000 IDU front panel provides
monitoring and control of the MTX5000 system. The color LCD
display panel with touch screen and the function keys are used
to select control and diagnostic menu screens for both the IDU
and the ODU.
The user interacts with the system through the touch-screen or
function keys. The user interface is broken into a normal user
mode and a system setup or advanced features mode.
Normal user mode menus permit basic radio control without
exposing you to the more complicated setup features available in
the advanced features sections. The advanced features can be
password protected to prevent an unwitting user from changing
critical settings.
Option buttons displayed on the IDU color LCD display panel are
used to control Preset selection, RF band selection, channel
selection, offset selection, antenna selection, antenna
polarization, transmitter operation (on or off), power (low or
high), and to monitor the status of the IDU and ODU. For
additional information, see the “Routine Operation” Chapter on
page 3-1.
The front panel color LCD display panel is also used to select
local or remote control operation of the MTX5000 system.
Remote Mode Operation The MTX5000 system may also be
operated from a remote location via the ETHERNET connector
mounted on the rear panel of the IDU. The IDU can be
connected to a PC at a remote location via your web browser.
The remote mode allows you to control the MTX5000 in the
normal user mode from the remote location using the PC display,
mouse, and keyboard. You cannot perform system setup
advanced features from the remote location.