5
4
In case of transparent mode original NIT (if any) will be passed to the output.
Other parameters:
Operating mode - this parameter switches device between two operating modes - transparent or multiplexed mode.
In case of transparent mode, original transport stream passes to modulator without any modifycations. Transparent
operation mode supports 2k and 8k modulation modes.
In case of multiplexed mode all multiplexing features are enabled (NIT generation, service ltering). Modulator can work
in 2k modulation mode only in multiplexed case.
A device will be restarted after switching this parameter, and will start operating after 10 seconds.
"Timing zone" selection used for system clock only, and it does not affect the output stream. This parameter exists in both
operating modes, but in case of multiplexed mode, the parameter is moved to "DVB-T Output/Stream" control panel.
DVB-T Output / Stream section (Multiplexed mode only)
Figure 7. OFDM Output/Stream parameters of ttx312
Output stream parameters can be congured in this section. The most important parameters are Stream ID and Network
ID. User must ensure that Network ID number is identical in all broadcasting equipments, and Transport stream ID must be
unique for every modulator or other streaming equipment.
“Private Data Specier” eld optionally can be used to identify the broadcaster or country. It should be assigned according to
EN 101 162 specication. All allocated values can be nd here: http://www.dvbservices.com/identiers/private_data_spec_id
Hexadecimal value should be entered here. The descriptor will be used together with LCN descriptor. If unsure - enter
zero. In that case the Private_Data_Specier will not be used at all.
"Network Name" used in NIT (Network Identication Table) and it represents broadcaster.
"Date/Time source" selects the source of the clock. TDT (Time and Date Table) will be passed to the output from selected
source. Also a system clock will capture current time values from this source.
"Timing zone" selection used for system clock only and it does not affect the output stream. TOT (Time Offset Table) is
passed transparently to the output from selected source, which carry timing zone information to the end-user.
"NIT Enable" parameter allows to turn On/Off NIT generation.
"EPG Multiplexing" parameter allows to turn On/Off multiplexing of EPG (Electronic Program Guide). The system will
multiplex EPG (EIT) if this parameter is turned on. EPG multiplexing part takes original EIT (Event Information Table),
modies StreamID, NetworkID values, and sends the stream to the output of multiplexer. EIT will be passed (multiplexed)
for enabled services only.
New button "Save and RUN" will appear if any value of this section was changed. Press it to save all changes and run
the system with modied values.
Next important part of this section is NIT conguration. Broadcaster can describe whole network there, so receivers (TV, set-
top-boxes) will be able to scan all channels automatically. The most important note to remember - Network ID number must be
identical in all broadcasting equipments and Transport stream ID must be unique for every modulator or other streaming equipment.
Enter NetworkID and StreamID values in "New Stream Description" table to start describing a stream (the output of each
modulator in the system). New empty record for that stream will appear above that table. Press sign to expand a description
and add all necessary descriptors for that stream. Select a descriptor (probably only "terrestrial_delivery_system_descriptor"
will need) from the list and press "Create new descriptor" button. New empty descriptor will be added. Press onto again
to expand stream description. New inserted descriptor will be found. Press onto to edit it's values (see Figure 8).
Figure 8. Terrestrial descriptor
Figure 5. Service details
List of all streams and other parameters will appear. Some streams will have icons, which indicates the type of the stream.
Following icons are possible:
- Sound stream - Teletext
- DVB Subtitles - Video
A language code will be visible in round brackets if presented in the stream.
A lock sign identiers conditional access streams, which affects a stream or a whole service (like in example above).
Most of the streams of the service can be disabled (ltered) by unchecking "Enabled" check box.
The service name and service provider name can be changed here.
"Monitoring" check box turns on monitoring of PMT version changes. If it is checked, new PMT table will be reloaded if
the version of the table is changed. New appeared streams will be added to the service automatically. Disappeared streams
will be removed from the service as well. The device does not take into account possible bit rate overow of new multiplex.
User must take care about it. Use this feature only in case if it is necessary. If unsure, leave it unchecked.
"Scrambled" ag can be switched on/off. If the ag is off, SDT table will be generated without "scrambled" ag and all CA
descriptors will be removed from the service.
Press "Update program information" button to modify details of the service.
Device will try to leave Service ID and PIDs original if there are no any PID conicts. However, user can modify this
information manually. Check “Other ID” or “Other PID” checkbox to enter new information. In this case, user is responsible
to enter correct PID and service ID to avoid any PID conicts with other services in a multiplex.
NOTE: "Enable services" button will need to be pressed to save all the changes and for them to take effect.
DVB-T Output section
Figure 6. OFDM parameters of ttx312 control panel
There are three tables in this section - modulator parameters, RF parameters and other parameters.
Modulator parameters:
Modulation - modulation type. Possible values: QPSK, QAM16, QAM64
Bandwidth - 7 or 8 MHz
Guard interval - 1/4, 1/8, 1/16, 1/32
Code rate - 1/2, 2/3, 3/4, 5/6, 7/8
Cell ID: - Any value 0..65535 can be entered.
Mode: - 2k/8k (2k only in case of multiplexed operating mode)
RF parameters:
RF On/Off - Allows to switch RF On or Off at the output
Saw lter - Enable or disable 8 MHz (or 7 MHz) bandwidth saw lter's at intermediate (36 MHz) frequency. If
the frequency offset ±166/125 kHz is used, a lter will be switched off automatically.
RF Frequency - Output frequency of modulated COFDM signal. Step - 0.5 MHz.
RF Offset - Output frequency offset ±166 kHz or ±125 kHz in 7 MHz bandwidth case.
Attenuator - RF Output attenuation in 0.0 .. 15.5 dB range.
NOTE: terrestrial_delivery_descriptor in NIT will be changed automatically after a change of any modulation parameters
in multiplexed operating mode. Open "DVB-T Output/Stream" tab and press "Save & Run" to save new values of descriptor.
