Real Time

Carrier DVB-T/H

Digital Video Broadcasting Terrestrial (DVB-T, ETSI EN 300 744) is the most popular digital terrestrial transmission system in the world. It has been successfully deployed in the UK, Germany, Sweden, Finland, Spain, Italy, Netherlands, Switzerland, Singapore and Australia. An image would be good to show the different standards used around the world. DVB-T trials are on-going in Malaysia, Thailand, Vietnam, Ukraine, Azerbaijan, Croatia, South Africa and other countries.

Based on coded orthogonal frequency divisional multiplexing (COFDM) and QPSK, 16 QAM and 64 QAM modulations, it is the most sophisticated and flexible digital terrestrial transmission system available today. DVB-T allows service providers to match, and even improves on, analog coverage - at a fraction of the power. It extends the scope of digital terrestrial television in the mobile field, which was simply not possible before, or with other digital systems.

Digital Video Broadcasting Handheld (DVB-H) , extension to DVB-T, is suitable for small screens, handheld portable and mobility reception. Despite the success of mobile DVB-T reception, the major concern with any handheld device is battery life. The power consumption of DVB-T front-end is too high to support handheld receivers that are expected to last from one to several days on a single charge. The new DVB-H standard addresses this requirement of broadcasting to handhelds. A time-slicing mechanism allows receivers to switch off for inactive periods, leading to power savings of approximately 90%. The other major requirements of DVB-H were an ability to receive 15Mbits per second in an 8 MHz channel and in a wide-area single frequency network (SFN) at high speed.

1. Basic

State

Choice: On |Off

Default: On

Double-click or use the drop-down menu to control the operating state of the carrier.

Format

The format of the carrier.

Frequency Offset

Range: -40.0 to 40.0 MHz

Default: 0.000000 Hz

Set the frequency offset for the carrier relative to the signal generator’s frequency setting. The valid range will be different for every format due to the different over-sampling ratios.

For example, for 2 carriers configuration, set the center frequency of signal generator to 1 GHz, and make the two carriers distributed on the both sides of the center frequency with 5 MHz offset each. Therefore, the actual frequency of each carrier would be 1GHz+5MHz and 1GHz-5MHz respectively.

Window Length

Range: 0 to 32

Default: 4

Set the window length of OFDM symbol.

Initial Phase

Range: 0 to 359 degrees

Set the initial phase of the carrier.

Power

Range: -50 to 0 dB

Set the carrier’s power relative to the signal generator’s amplitude setting.

2. DVB-T Settings

Number of Super Frames

Range: different settings are corresponding to different range values.

Set the number of super frames, which is composed of four frames, and the transmitted signal is organized in frames.

8K mode - Each frame consists of 68 OFDM symbols and each symbol is constituted by a set of K = 6817 carriers

2K mode - Each frame consists of 17 OFDM symbols and each symbol is constituted by a set of K = 1705 carriers 

For DVB-T 8k mode, the frame structure can be shown as follows:

RS Encoder

Choice: On |Off

Default: On

Double-click or use the drop-down menu to enable or disable the RS encoder. For DVB-T/H, when the RS encoder is off, the payload is treated as the output of a RS encoder and fed into the convolutional interleaver directly.

Transmission

Choice: Hierarchical | Non Hierarchical  

Default: Non Hierarchical

Double-click or use the drop-down menu to select Hierarchical or Non Hierarchical Transmission. When Hierarchical is selected, the following cell configuration( HP Code Rate and LP Code Rate) will be enabled.

Alpha

Choice: 1 | 2 | 4  

Default: 1

Double-click or use the drop-down menu to select the Alpha from 1/2/4, which will be effective only when Transmissionis Hierarchical.

Alpha is the minimum distance separating two constellation points carrying different HP-bit values. Non-hierarchical transmission uses the same uniform constellation as the case with α = 1.

Mode

Choice: 2K | 4K | 8K  

Default: 2K

Double-click or use the drop-down menu to select the mode.

DVB-T has two kinds of sub-carrier mode, in short 8k mode and 2k mode.

Bandwidth

Choice: 5MHz | 6MHz | 7MHz | 8MHz  

Default: 8MHz

Double-click or use the drop-down menu to select the bandwidth.

Modulation Type

Choice: QPSK | 16 QAM | 64QAM  

Default: QPSK

Double-click or use the drop-down menu to select the modulation type .

The DVB-T system adopts Orthogonal Frequency Division Multiplex (OFDM) transmission. The modulation type for all the data carriers in one OFDM is either QPSK, 16-QAM, 64-QAM, non-uniform 16-QAM or non-uniform 64-QAM constellations.

Guard Interval

Choice: 1/4 | 1/8 | 1/16 | 1/32 

Default: 1/4

Double-click or use the drop-down menu to select the guard interval.

The purpose of the guard interval is to introduce immunity to propagation delays, echoes and reflections, to which digital data is normally very sensitive.

Guard Interval (Tg) is a part of waveform which is copied from the rear and added at the front of a carrier. Therefore, a OFDM symbol period consists of Tu and Tg, which is called cyclic prefix. At the DVB-T receiver side, as long as the signal delay is less than Tg, the receiver will capture the original signal correctly. 

Cell ID Enabled

Choice: True | False

Default: False

Double-click or use the drop-down menu to control the cell ID state.

Cell ID

Range: 0 to 65535

Default: 0

Set the cell ID.

The most significant byte of the Cell ID, i.e. b₁₅ - b₈, shall be transmitted in super-frames with the frame number 1 and 3. The least significant byte of the Cell ID, i.e. b₇ - b₀, shall be transmitted in super-frames with the frame number 2 and 4. 

This cell is only enabled when Cell ID Enabled is True.

Code Rate

Choice: 1/2 | 2/3 | 3/4 | 5/6 | 7/8

Default: 1/2

Double-click or use the drop-down menu to select the code rate of convolutional coder. This cell is only enabled when Transmissionis Non-Hierarchical.

In order to achieve hierarchy, two different code rates may be applied to two different levels of the modulation.

HP Code Rate

Choice: 1/2 | 2/3 | 3/4 | 5/6 | 7/8

Default: 1/2

Double-click or use the drop-down menu to select the HP (High Priority) code rate of convolutional coder. This cell is only enabled when Transmissionis Hierarchical.

LP Code Rate

Choice: 1/2 | 2/3 | 3/4 | 5/6 | 7/8

Default: 1/2

Double-click or use the drop-down menu to select the LP (Low Priority) code rate of convolutional coder. This cell is only enabled when Transmissionis Hierarchical.

Multi-path Channel

Default: OFF

Click in the right side of the cell to open the Multi-path Channel configuration window.

The performance of DVB-T system through simulation with two channel models can be explored in this step, and up to 20 paths are supported.

• P1 - portable reception, Simulating Rayleigh fading 

• F1 - fixed reception

  Besides, User Defined provides a more flexible way configuring each path's attenuation ρ, relative delay τ and phase shift from scattering θ.

  1. Edit the parameters values in the table directly.

  2. Or, click on the button, and select a fading file (*.fading) previously configured.

  3. When you finished editing the user defined parameter configuration, click on button to make a copy.

     I	ρi Attenuation of the i'th path	τi [μs] Relative delay of the i'th path	θi [rad] Phase shift from scattering of the i'th path
     1	0,057 662	1,003 019	4,855 121
     2	0,176 809	5,422 091	3,419 109
     3	0,407 163	0,518 650	5,864 470
     4	0,303 585	2,751 772	2,215 894
     5	0,258 782	0,602 895	3,758 058
     6	0,061 831	1,016 585	5,430 202
     7	0,150 340	0,143 556	3,952 093
     8	0,051 534	0,153 832	1,093 586
     9	0,185 074	3,324 866	5,775 198
     10	0,400 967	1,935 570	0,154 459
     11	0,295 723	0,429 948	5,928 383
     12	0,350 825	3,228 872	3,053 023
     13	0,262 909	0,848 831	0,628 578
     14	0,225 894	0,073 883	2,128 544
     15	0,170 996	0,203 952	1,099 463
     16	0,149 723	0,194 207	3,462 951
     17	0,240 140	0,924 450	3,664 773
     18	0,116 587	1,381 320	2,833 799
     19	0,221 155	0,640 512	3,334 290
     20	0,259 730	1,368 671	0,393 889

3. DVB-H Settings

Is DVB-H

Choice: True | False

Default: False

Double-click or use the drop-down menu to select if this configuration is DVB-H. If this value is true, DVB-H TS files are required for payload. 

DVB-H system, carrying multimedia data over digital terrestrial broadcasting networks, is aiming at handheld terminals. Due to its mobility characteristics, constraints on power supply and varying transmission are the major concern in DVB-H system.

Interleaver

Choice: Native Interleaver | In-depth Interleaver

Default: Native Interleaver

Double-click or use the drop-down menu to select the interleaver.

• native interleaver : 2k mode /4K mode/8k mode

• In-depth symbol interleaver : 2K and 4K-modes, for further improving their robustness in mobile environment and impulse noise conditions.

Time Slicing

Choice: ON | OFF

Default: OFF

Double-click or use the drop-down menu to select whether the time slicing flag is set in TPS. This cell is only enabled when Is DVB-H is True.

Time-slicing is aiming at reducing the average power consumption of the terminal and enabling smooth and seamless service handover. For one thing, time-slicing enables a receiver to stay active only a fraction of the time, while receiving bursts of a requested service. For another, It also supports the possibility to use the receiver to monitor neighboring cells during the off-times (between bursts). In other words, time slicing is a method to deliver MPE (Multiprotocol Encapsulation) sections and MPE-FEC sections in bursts.

MPE-FEC

Choice: ON | OFF

Default: OFF

Double-click or use the drop-down menu to select whether the MPE-FEC flag is set in TPS. This cell is only enabled when Is DVB-H is True.

MPE-FEC (Multiprotocol Encapsulation - Forward Error Correction) is aimed at improving the C/N and Doppler performance in mobile channels and improving the tolerance to impulse interference. 

4. Data Source Settings

Useful Bit Rate

The useful bit rate. The bit rate is determined by current bandwidth, encoding, modulation and framing configurations.

Supported File Size

The supported file size for current settings.

Payload

The TS payload settings.

Data Source Type

Choice: Test Pattern | Demo File | TS File

Default: Test Pattern

Double-click or use the drop-down menu to select which type to be used as the data source.

If "TS File" is selected, "File Name" is required.

Learn more about the different Data Source Types, refer to the page Data Source Type.

Pattern Bits

The data bits used as test pattern.

Click the right button to open "Data Pattern Selection" dialog and select test pattern to use.

SYNC Insertion

Choice: True | False

Default: False

Double-click or use the drop-down menu to determine whether a SYNC byte (0x47) should be inserted into the test pattern.

Video Type

Choice: NTSC | PAL

Default: PAL

Double-click or use the drop-down menu to select whether the PAL or NTSC file is demo File. This cell is only enabled when Data Source Type is Demo File.

There are two predominant worldwide video-based source material formats, shown as follows:

• NTSC: National Television System Committee, the system used in America & Canada

• PAL: Phase Alternating Line, the system used in Western Europe and Australia

Table 2 NTSC parameters list

Table 3 PAL parameters list

File Name

Click on in the right side of the cell, and select the file name you set as payload.

Auto Stuffing

Choice: ON | OFF

Default: ON

This cell is only enabled when Data Source Type is TS File. Double-click or use the drop-down menu to select whether or not to use auto-stuffing to agree with transport bit rate.

Loop Play

Choice: ON | OFF

Default: ON

This cell is only enabled when Data Source Type is TS File. Double-click or use the drop-down menu to determine whether or not to modify the TS file to make it suitable for loop play. 

File Size

The size of opened file.

Bit Rate

The bit rate of the opened file.

Play Time

The time that file can be played.