DekTec DTC-300 StreamXpress - Manual (Page 25)

DTC-300-SP – StreamXpress
USER MANUAL
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For example, if the modulated channel is 6 MHz wide and the RF channel selected is 576Hz, the RF
signal will span between 573MHz and 579MHz.
NOTE: The StreamXpress can playback at any channel frequency but depending on the modulation
format and the world region, commercial receiver built in TV or setopbox may have fixed channel
lined up. Consult the local channel line up to make sure that the channel frequency selected in the
StreamXpress will “fit” a specific RF channel in the commercial channel allocation table.
For example, in the US, channel 7 terrestrial channel is allocated between frequency 174MHz and
180MHz, to feed a TV/setopbox to channel 7, the user must use the center channel 177MHz
representing the center of allocated RF channel 7.
3.5.1.2 Rate and symbol rate settings
A type of modulation and settings such as bandwidth, forward error correction will dictate the
symbol rate and therefore data rate throughput that need to be fed to the modulator. As with most
modulator the data rate needs to be very close to the theoretical data rate in order to function
properly.
When setting the modulation parameters, the StreamXpress will calculate and display the output rate
or symbol rate required to feed the modulator. If the file bitrate is lower than the required data rate/
symbol rate for that modulation the StreamXpress can remultiplex the file in real-time to adapt to the
required channel rate. The user can do this by ticking the RMX box.
If the datarate of the file is higher than the required data rate/symbol rate, the file cannot be played
out properly and the TS rate display will turn red or the Out rate will turn orange if the RMX box is
ticked. In this case choose a lower datarate file or adjust the modulation parameters.