Promax MO-160 Manual De Usuario página 63

USER'S MANUAL. MO-16X
Whenever possible, it is advised to use an input bit rate considerably lower than
the nominal value given in the DVB-T specification. Otherwise, an input rate too close to
the required value might eventually lead to overflow of the TS packet buffer
implemented in the modulator.
The modulator can be configured to generate any of the transmission modes
listed in the DVB-T specification. In hierarchical modes, the HP and LP streams can be
encoded with different convolution code rates. The channel bandwidth can be set by the
user to 6, 7 or 8 MHz as required by the application.
The modulator is frequency agile. The user can select an RF output frequency
between 45 and 875 MHz
is internally set by the modulator and varies between 31 and 36 MHz depending on the
selected RF frequency. The RF output can be switched off, in which case the IF
frequency is fixed at 36 MHz. The polarity of the IF/RF spectrum (inverted or non-
inverted) can be selected by the user.
In MFN operation, the MO-16X is capable of filtering out up to 16 Packetized
Elementary Streams (PES) identified by their PIDs. The MPEG-2 TS is not actually re-
multiplexed because the TS tables are not updated, only the PES's are eliminated to
help reduce the bit rate. This feature finds its application in, for example, trans-
modulating a high-bit-rate DVB-S signal to DVB-T.
The modulator has a DVB-S IF input and output (loop-through). The IF and
Symbol Rate can be set up by the user. Furthermore the LNB can be powered up and
the 22 KHz signal can be generated.
The MO-16X has been designed to work in Multi Frequency Networks (MFN).
Single Frequency Network (SFN) operation is not currently supported. The quality of the
output signal has been optimised for 8 MHz channels. The MER measured at IF in this
case is approximately 40 dB in master mode.
The operation of the MO-16X is done via the front panel LCD display and
controls. The modulator can be easily configured by navigating through a rather intuitive
set of menus. A couple of LEDs located on the front panel signal the existence of errors
in the modulator or whether the equipment is properly powered.
*
Depending on the acquired model, it has a SPI or DVB-S IF, see the Table 1
04/2008
*
in steps of 1 Hz. In normal operation, the IF output frequency
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