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Views of the DVB-T/T2/C - 2xDVB-T (COFDM) TTX-420C R81613 transmodulator
Key features
- conversion of DVB-T/T2/C signals to DVB-T COFDM,
- conversion of multiple signals from two DVB-T/T2/C multiplexes to 2 neighboring DVB-T multiplexes,
- possibility to create one DVB-T multiplex from two different DVB-T/T2/C multiplexes,
- transparent regeneration of DVB-T/T2/C stream (without changing the structure or services);
- change of the RF channel of DVB-T multiplex,
- selectable channels and services in output stream (in multiplexing mode)
- easy control via RJ-45 port,
- two CI ports (multi-channel descrambling of pay-TV)
- management via the Internet,
- access to event history (logs),
- automatic gain control (AGC).
TERRA TTX420C R81613 transmodulator is used for reception of DVB-T/T2/C signals and for change of their parameters (regeneration, filtering, descrambling, retransmission in different RF channels etc.) according to the needs of the project. The device can receive whole sets of channels from two DVB-T/T2/C multiplexes, both free-to-air and encrypted, and convert them into two neighboring DVB-T multiplexes with maximum data rate allowed by the DVB-T standard, i.e. 31.68 Mbps. In practice, each multiplex can carry 6 SD channels or 2-3 HD channels. The administrator of the system selects the required channels from the input streams and forms two DVB-T multiplexes. Alternatively, one DVB-T multiplex can be programmed from channels coming from two different DVB-T/T2/C multiplexes. In each case, it is neceeesary to remember about 10% safety margin when determining the maximum bit rate for the whole multiplex (typically the ultimate bit rate of a multiplex in multiplexing mode should not exceed 29 Mbps). The output DVB-T COFDM multiplexes are usually distributed to users by a passive network composed of RF splitters/taps. Such a solution is especially convenient in modern hotel TV systems distributing a variety of satellite channels, including HD broadcasts.
The application of TTX-420C R81613 transmodulator allows for distribution of digital TV channels in situations when the signal received by the antenna cannot be directly amplified or converted to a different frequency due to high BER and low MER levels. It happens in areas with low signal quality.
The regeneration process consists of receiving the DVB-T/T2/C signal, demodulating it to the transport stream, and then re-modulating RF signals as a new COFDM multiplex (frequency converter function). MER (modulation error rate) at the output of the device is not lower than 35 dB, which allows for the distribution of the digital multiplex even in very large MATV systems.
The device can operate in two modes:
- transparent mode - the decoded transport stream is not modified and is directly applied to the COFDM modulator - without PID filtration;
- multiplexing mode - the device examines the decoded transport stream (measures the bit rate, updates SI arrays) and optionally filters programs and services.
Thanks to RJ-45 Ethernet port, the programming of the TTX-420C R81613 panel is performed via a web browser.
The TTX-420C R81613 panel has two CI slots that in the case of receiving encrypted channels must be equipped with suitable conditional access modules (CAM) with dedicated smart cards allowing decryption of these channels.
A great advantage of the Terra device is easy integration with other components:
- IPTV streamers for management and distribution of satellite, terrestrial and cable DVB channels within Ethernet (LAN) networks based on twisted-pair cabling,
- optical transmitters for transmission TV programming via optical links,
- other receiving and signal processing devices (broadband and channel amplifiers, analog and digital modulators).
Customers can also order DVB-T/T2/C--> DVB-C (QAM) transmodulators:
- DVB-T/T2/C to 2xDVB-C (QAM) Terra TTQ-420C (two CI slots)
- DVB-T/T2/C to 2xDVB-C (QAM) Terra TTQ-420

View of the information window of TTX-420C R81613 module
(among others: input level, SNR, VBER parameters)
With these parameters, the maximum bandwidth of each of the two DVB-T multiplexes
is 31.68 Mbps, in compliance with the DVB-T standard
is 31.68 Mbps, in compliance with the DVB-T standard

The percentage of the usage of the available bandwidth in each multiplex

Notice: The transmodulator is compatible only with CI CAM modules (no support for CI+).
Notice: The transmodulator cannot change the original coding standard (e.g. from H.265 to H.264). The original standard remains unchanged.
Specifications:
Name | TTX420C | |||
Code | R81615 | |||
RF input | Frequency range [MHz] | 47 - 862 | ||
Power for a preamp [V/mA] | 12 / 100 | |||
Level/Impedance [dBμV/Ω] | 40 - 80 / 75 | |||
Loop through gain [dB] | -1 ±1 | |||
Standard | DVB-T | DVB-T2 | DVB-C | |
Modulation | QPSK, QAM16, QAM64 | QPSK, QAM16, QAM64, QAM256 | QAM16, QAM32, QAM64, QAM128, QAM256 | |
RF channel width [MHz] | 7 or 8 | 7 or 8 | - | |
Symbol rate [Ms/s] | - | - | 1...7.2 | |
FEC | 1/2, 2/3, 3/4, 5/6, 7/8 | 1/2, 3/5, 2/3, 3/4, 4/5, 5/6 | - | |
Roll-off coef. [%] | - | - | 15 | |
RF output | Frequency range [MHz] | 100... 858, step 0.1 | ||
Level/Impedance [dBμV/Ω] | 90 ±2 / 75 | |||
Spurious level [dB] | < -60 | |||
Loop loss [dB] | ≤ 2.5 dB | |||
MER | ≥ 38 dB (100-780 MHz); ≥ 35 dB (780-860 MHz) | |||
Modulation | QPSK, QAM16, QAM64 | |||
Channel width [MHz] | 7/8 | |||
Guard interval | 1/4, 1/8, 1/16, 1/32 | |||
FEC | 1/2, 2/3, 3/4, 5/6, 7/8 | |||
FFT mode | 2K / 8K | |||
Output level adj. [dB] | 0...-15 (step 1) | |||
Transport stream parameters | Max. bitrate [kb/s] | 31680 | ||
Max. number of PIDs | No limit | |||
- | - | |||
Other specs | Ethernet port | IEE802.3 10/100 Base-T (RJ45) | ||
Power [V/A] | 12/0.65 | |||
Oper. temp. [ºC] | 0...50 | |||
Dimensions [mm] | 48.5x198x112 | |||
Weight [kg] | 0.9 |