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Mini headend MMH-3000+ with maxi potential
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of decoding, processing, converting analog TV, DVB-T, DVB-S, DVB-C, A/V signals
This article is complementary to the Modular Headend TERRA MMH-3000 item describing the basic features of the TERRA MMH-3000 headend.
The headend is intended for facilities and institutions requiring centralized management of the programming distributed in the SMATV system. No need for additional devices (satellite receivers) connected to the televisions makes this solution particularly attractive e.g. for hotels and hospitals.

A headend or head station is a set of professional satellite (and often DVB-T) receivers, decoders, modulators, remodulators, converters etc. The output signals are distributed over an RF network and can be received by every (suitable) TV set connected to any outlet. Such a system can be installed both in newly built facilities and in existing buildings equipped with typical RF distribution networks based on splitters and taps or done in pass-through arrangement.
The characteristics of the Terra MMH-3000+ headend
MMH-3000+ is a very flexible solution. Depending on the requirements and needs of the investor, it can be used to implement one or more of the following projects:
  • converting DVB-S/S2 FTA channels into analog VHF/UHF channels,
  • decoding DVB-S/S2 encrypted channels and modulating unencrypted analog VHF/UHF channels,
  • converting DVB-S/S2 FTA channels into DVB-T multiplexes,
  • decoding DVB-S/S2 encrypted channels and creating unencrypted DVB-T multiplexes,
  • converting DVB-T multiplexes (encrypted and unencrypted) into analog VHF/UHF channels,
  • injection of signals from analog cameras or media players as analog VHF/UHF channels or digital DVB-T multiplex(es),
  • creating "private" DVB-T multiplexes composed of selected satellite and/or terrestrial TV channels and video feeds from security cameras and/or media players.
Depending on the desired outcome, the headend has to be equipped with the appropriate set of modules. All modules are described in detail later in this article.
Fig. 1. Modular design of the MMH-3000+ headend provides the possibility to remodulate (transmodulate)
a wide range of input signals. The output signals may include PAL channels (in installations for older TVs),
digital DVB-T multiplexes (for modern TVs), or both the signals.
List of modules for Terra MMH-3000+ headend
Input signal
Output signal
Purpose / cooperation with
regeneration, conversion,
EPG multiplexing,
NIT generation,
PMT monitoring
R81709TRX-360MPEG-TSDVB-TRDC-316, RDC-313, MD-330
R81715CT-311DVB-TDVB-Tchannel conversion
R817101RDC-316 CIDVB-S/S2PAL
R817121DM-316MPEG-TSPALRDC-316, RT-316
DM-313, TRX-360
Base Unit UC-380 R81700
The base unit UC-380 R81700 houses the components of Terra MMH3000+ headend. It can be put in a 19" rack cabinet. The unit incorporates power supply and cooling system, RF amplifier, and intelligent data bus. It may hold up to 8 individual modules for reception/modulation/transmodulation of various kinds of signals.
Base Unit UC-380 (for Modular Headend MMH-3000)
Fig. 2a. Base unit UC-380 R81700

Fig. 2b. View of an MMH3000+ headend: the UC-380 R81700 base unit with a set of modules
MPEG2 TS (Transport Stream)
Before a detailed analysis of the components of the MMH-3000+ headend it is worth paying attention to the fact that almost all the modules have a built-in MPEG2 TS interface (Fig. 3).
Fig. 3. The MPEG2 TS interface implemented in MMH-3000+modules
This interface enables the transmission of the received channels from a whole satellite transponder or DVB-T multiplex between the components of the headend, in the form of a digital MPEG2 stream. Then, each "output" module can be used for selecting a desired channel from the stream in order to provide a modulated RF channel with the required modulation (PAL, COFDM, QAM).
Fig. 4. The application of MPEG2 TS interfaces.

The first module receives all channels from one satellite transponder,
and feeds them as MPEG2 TS to the second module.
The second module is to select one channel and provide modulated RF signal.
QPSK-PAL Transmodulator RDC-313 R81710
The RDC-313 R81712 module receives and converts one satellite channel into PAL channel in terrestrial TV band and provides MPEG-2 stream from the received transponder to other modules.
QPSK CI Receiver RDC-313 (QPSK/PAL, for MMH-3000 headend)
Fig. 5. The RDC-313 R81710 module
RDC-313 has CI slot enabling - after installing adequate CA module - reception of encrypted programs. If the headend is equipped only with RDC-313 modules, the investor must apply for cards decoding individual channels. The advantage of this solution is higher stability than in the case of multi-stream CA modules.
The built-in VSB modulator with adjustable output level allows for efficient use of RF channels in the distribution system.
MPEG-2 TS Decoder / PAL Modulator DM-313 R81712
DM-313 R81712 modules are used in MMH-3000+ headends that distribute analog RF channels. They are intended to cooperate with RDC-313 receivers. One module decompresses a desired channel from MPEG-2 transport stream provided by the RDC-313 receiver and converts one satellite channel into PAL channel in terrestrial TV band. DM-313 and RD-313 can cooperate with each other only within channels from the same transponder. The DM-313 module has been also equipped with VSB PAL modulator with adjustable output level, which allows for efficient use of RF channels in the distribution system. The use of DM-313 is especially recommended for distribution of satellite FTA channels located on the same transponder.
NOTICE: The range of products also includes RDC-316 R817101 and DM-316 R817121 modules. These modules can receive DVB-S/S2 MPEG-4 signals. The RDC-316 module equipped with a DSB modulator is widely used in the case of headends distributing DVB-T signals. Such a case is presented later in this article.
Fig. 6. Application of RDC-313+DM-313 modules for receiving 4 encrypted channels from one transponder.
This type of configuration requires to use appropriate multi-stream conditional access module
(to be placed in the RDC-313 module).
VSB Modulator MT-310
The MT-310 R81708 modulator allows for injection of external baseband audio/video signals coming from a CCTV camera, DVD player, computer or other device generating audio-video content. On a selected RF channel, the owner of the facility can introduce e.g. commercials.
MMH-3000+ and modern TVs - why to choose DVB-T standard in hotel systems?
  • HD quality option.
  • Identical image quality in the whole distribution network - no quality degradation connected with digital signal distribution in large installations, where in the case of analog channels the decreasing C/N ratio can result in results in noise and interference. All DVB-T receivers in the facility can provide images in the same quality.
  • RF spectrum economy - in facilities with a wide range of channels and additional functions, not without significance is the fact that COFDM modulation can save the TV band up to 6 times.
  • Uniformity of emission standards - after the transitional period, analog TV broadcasts are/will be switched off.
Conversion of Baseband Audio/Video to DVB-T
MMH-3000+ allows for injection of of external baseband audio/video signals coming from a CCTV camera, DVD player, computer or other device generating audio-video content in the form of digital DVB-T multiplex. The operation is performed in two stages, by converting analog video/audio signals coming from the sources into MPEG-2 coded transport streams in the MPEG-2 encoder MD-330 R81713, and then feeding them to the TRX-360 R81709 DVB-T modulator (COFDM) that distributes them in an RF network as channels in the DVB-T multiplex.
Fig. 7. Application of MD-330 and TRX-360 modules for injection of external signals as a DVB-T multiplex
The MD-330 encoder allows for simultaneous conversion of three analog signals into three transport streams with bit rates from 0.5 Mbps to 15 Mbps (each channel). Depending on the kind of source signal, each stream can have variable (VBR) or constant (CBR) bit rate.
Fig. 8. Practical application of DVB-T modulator TRX-360 R81709 and MPEG-2 encoder MD-330 R81713. Three images from analog CCTV cameras are seen in the system as three channels of digital DVB-T multiplex.
The TRX-360 modulator has three more free inputs for MPEG streams. They may be connected to another encoder or to other modules of the headend.
Remultiplexer and DVB-T Modulator (COFDM) - TRX-360 R81709
The mentioned above DVB-T modulator TRX-360 R81709 is a powerful tool allowing for creation and distribution of "private" digital DVB-T multiplexes. It can (re)multiplex up to 6 transport streams (MPEG-2 TS) from any modules of the TERRA MMH-3000+ headend and convert them into COFDM modulated DVB-T RF channel (mux). The multiplex may include selected DVB-S/S2 satellite channels (from different transponders or even satellites), DVB-T channels, and signals from CCTV cameras or media players (see the section above).
DVB-T Modulator (COFDM) for TERRA MMH-3000
Fig. 9. Remultiplexer and DVB-T Modulator TRX-360 R81709 with 6 MPEG2 TS inputs
Distinguish features of the TRX-360 modulator:
  • six TS inputs intended for cooperation with any TERRA modules equipped with TS outputs (RDC, DM, TDX…),
  • DVB-T modulation,
  • adjustment of stream parameters,
  • service filtering (PID),
  • generation of NIT (Network Information Table) and LCN (Logical Channel Number),
  • maximum output bit rate: 31,66 Mbps.
Fig. 10. View of the basic configuration window of the TRX-360 modulator.
In this example - the input stream containing a whole satellite transponder fed to the first TS input of the device has a temporary bit rate of 42.59 Mbps (other inputs are not used). Because the maximum bit rate at the output of the device cannot exceed 31.66 Mbps, it is impossible to put the whole transponder into one DVB-T multiplex.
Fig. 11. The content of the transponder - three satellite HD channels. To ensure stable operation of the DVB-T modulator, only two HD channels can be put into one DVB-T multiplex. Distribution of the third HD channel would require to employ another DVB-T modulator.
Fig. 12. It is not recommended to make use of the maximum bitrate. In the case of distributing satellite TV channels, the safety margin should be 10-15% of the maximum capacity. The maximum bitrate at the output depends on: the type of modulation, channel width, "Guard Interval" and FEC parameters.
In systems with very old cabling, it may be necessary to increase Guard Interval parameter,
which will somewhat decrease the maximum output bitrate.
How to check the bitrate of a satellite channel/transponder?
Planning the set of channels in a DVB-T multiplex, the installer has to take into account the bit rates of the channels that are to be distributed in the network. This is mainly due to the limited capacity of digital multiplexes. As mentioned above, the maximum capacity of a DVB-T multiplex with the guard interval of 1/32 and FEC of 7/8 is 31.66 Mbps. The assumption that such multiplex can carry six SD channels or two HD channels is generally true, but there may be exceptions. So, how many SD or HD channels can be put in a single multiplex?
There are several ways to solve the problem. The simplest one is to visit services like www.digitalbitrate.com or www.linowsat.de. They offer a range of statistics for multiple channels and transponders from all popular satellites, especially Hotbird and Astra. The statistics for individual channels can be recalled even up to a year back.
Fig. 13. Historical data from the www.linowsat.de website - maximum bitrates of some SD channels broadcast from Hotbird satellite on Jan. 22, 2011.
Fig. 14. The above figure presents bit rate values recorded for 7 days for the following channels: Eurosport HD, Canal+ Film HD, Canal+ Sport HD. It is obvious that the instantaneous values of the bit rates can be very changeable, especially in the case of HD sports channels (even up to 20 Mbps).
Knowing the bit rates of the channels that are to be distributed, the installer can appropriately select the components of the headend and configure the system.
Modernization of analog headends for distribution of satellite channels in DVB-T standard
The TRX-360 R81709 module has been designed to enable easy and fast adaptation of working analog TERRA headends to digital DVB-T standard. There is no need to purchase a new base unit or new satellite receivers/transmodulators.
Fig. 15. Simple adaptation of analog MMH-3000 headend to DVB-T. So far, the headend redistributed 6 satellite channels in the form of analog PAL channels. After equipping the base unit with the TRX-360 R81709 DVB-T modulator, any selected channels can be placed on a DVB-T multiplex. Interestingly, there is no need to switch off the analog PAL channels. What's more interesting, it is possible to distribute two independent channel packages, the analog one and the digital, with completely different content.
Conversion of DVB-S/S2 signals to DVB-T multiplexes
- a case study
The requirements for a modern headend include the ability to receive satellite SD and HD channels (also encrypted ones) and redistribute them in the DVB-T standard.
Below we present an example implementation of TERRA MMH-3000+ headend in a hotel. This example shows how to select the individual components of the headend that are to perform the required functions.
The programming capabilities of the presented headend:
  • distribution of 18 SAT FTA SD channels,
  • distribution of 12 SAT encrypted SD channels,
  • distribution of 3 SAT FTA HD channels,
  • distribution of 3 terrestrial DVB-T multiplexes,
  • distribution of video from security cameras and other external sources (PC, media player etc).
Fig. 16. Application of MMH-3000+ headend for the distribution of selected SAT TV channels in digital DVB-T standard. The output signals include eight DVB-T multiplexes (5 from TDX-311R81711 modules and 3 from TRX-360 R81709 modulators). The encrypted satellite channels are received in DVB-S standard. If they were broadcast in DVB-S2 standard, it would be necessary to replace the RDC-313 R81710 modules with RDC-316 R817101 ones.