background image

EN

19

6. -  Selecting the DVB-T output 

mode in DVBS2-COFDM 
transmodulators

The standard DVB-T defi 

nes various possible 

operation modes which enable the DVB-T signal 
generated to adjust to the conditions of the 
transmission channel. The signal for instance can 
travel through a very noisy channel (low C/N) but 
will bring with it reception errors. The signal may 
also reach the receiver through a number of paths, 
one main path and another or various secondary 
ones (ECHOES).

Put simply, we could say that the DVB-T operation 
modes can be characterised by the following:

    1 - Type of modulation
    2 - Level of protection against Errors
    3 - Level of protection against Echoes

In the following chart, one can see a subgroup 
of the possible DVB-T modes that indicates the 
information service output (Mbits/sg) that each 
one can transmit.
The greater the information service output of the 
DVB-T mode selected, the greater the number of 
TV and Radio services which can be transmitted 
through the signal.

NOTE:

 

We suggest choosing one of the DVBT modes 

from the chart. Those modes which have not been 
included have a lower information service output.

One the right hand side of the chart are the 
diff erent unit step functions (64 QAM 2/3, 64QAM 
3/4, 64QAM5/6, 64QAM 7/8), each one corresponds 
to a degree of protection against errors which the 
DVB-T signal can carry.

The higher the step selected, the greater the 
information service output (Mbits/sg) of the 
relevant DVB-T mode, although it´s level of 
protection against errors will be inferior and it will 
require a higher C/N to receive the signal.

We will now look at the level of protection against 
echoes.
To do so, one must select one of the four possible 
vertical axes that appear on the left side of the 
previous chart (GI=1/4, GI=1/8, GI=1/16, GI=1/32).

The further left the selected axis is, the greater the 
DVB-T mode´s information service output (Mbits/
sg) will be, but its level of protection against 
echoes will be lower, in other words, the maximum 
supported echo delay will be inferior.

GI=1/32

GI=1/16

GI=1/8

GI=1/4

31.67

30.16

27.14

24.13

30.74

29.27

26.35

23.42

29.03

27.65

24.88

22.12

26.13

24.88

22.39

19.91

64QAM 7/8

64QAM 5/6

64QAM 3/4

64QAM 2/3

Information service output (Mbits/sg) for
DVB-T signals with a 64QAM modulation
in 8MHz channels.

Summary of Contents for DVB-S2 COFDM

Page 1: ...Ref 563101 w w w t e l e v e s c o m DVBS2 COFDM EN User manual...

Page 2: ......

Page 3: ...ly unit 11 4 3 Amplifier 12 4 4 Universal programmer 13 5 How to use the product 14 5 1 Main menu 14 5 2 Extended menu 16 5 3 Parameters saving 18 6 Selecting the DVB T output mode in DVBS2 COFDM tran...

Page 4: ......

Page 5: ...DVB ET300744 FEC 1 2 2 3 3 4 5 6 7 8 Cell_id Selectable Bandwidth 7 MHz 8 MHz Output spectrum Normal Inverted Selec RF output Output frequency 177 266 474 858 MHz CH mode 45 862 MHz Frequency mode Thr...

Page 6: ...level 1 129 dB V typ DIN 45004B Max Power 16 W Frequency range 2 5 30 MHz Test socket 20 dB Gain 2 20 3 dB typ Maximum output level 2 129 dB V typ DIN 45004B Power supply unit 5629 Mains voltage 196 2...

Page 7: ...4VDC 5A T 0X Accessories 7234 Universal Programmer 5071 T03 T05 T 0X Mounting rail 50 cm 5239 T03 T05 T 0X Mounting rail 12 Modules PSU 56 cm 5301 19 Subrack frame 507202 T 0X Lockable cabinet with Ve...

Page 8: ...GM DVBS 2 COFDM PRGM DVBS 2 COFDM BROADBAND AMPLIFIER TEST 30dB 1 2 CLAC 3 Mounting 3 1 Wall mounting 7234 NOTE The use of both source outputs is recommended balancing the consumption For example 4 3...

Page 9: ...R 02340043001 003 CTRL PRGM DVBS2 COFDM PWR 02340043001 003 CTRL PRGM DVBS2 COFDM PWR 02340043001 003 CTRL PRGM DVBS2 COFDM PWR 02340043001 003 CTRL PRGM DVBS2 COFDM PWR 02340043001 003 CTRL PRGM DVBS...

Page 10: ...emodulates it by obtaining an MPEG 2 transport package The programming of the transmodulator operating parameters input frequency output channel modulation format and adaptation of services mainly is...

Page 11: ...CTRL DVBS2 COFDM PWR NOTES The power source can supply a maximum of seven DVBS2 COFDM T0X modules Whenever the demand of power exceeds 4A max current for each output it is necessary to distribute it b...

Page 12: ...es two input connectors to allow mixing of channels coming out from two different systems If only one of the inputs is used it is recommended to load the unused input with a 75 ohm terminator ref 4061...

Page 13: ...s Selection of parameter positioning of the cursor Modification of the parameter chosen by the cursor flashing short press Change menu long press Change between Principal and Extended menus long press...

Page 14: ...ector power supply enabled for the LNB the LED on the front of the module flashes until this condition disappears 5 Instructions for use Insert the programmer in the front connector of the module prog...

Page 15: ...Norm not inverted and Inv spectrum inversion In channel mode it lets you select an output channel from the table selected as well as the offset regarding the channel s receiving point frequency The p...

Page 16: ...are selected it will result in an output overflow and this condition is indicated MONITOR Occupancy 76 Max 80 MONITOR Overflow Occupancy values higher than 82 are not recommended If the occupation exc...

Page 17: ...4 Max 05 reset The recommended operating margins are as follows Optimum operation 0 6 High temperature 7 8 Excessive temperature 9 10 If the maximum recorded is outside the optimal range the installat...

Page 18: ...guage 5 3 Parameters saving Once a parameter is modified to the desired value in any menu normal or extended to save the settings press for three seconds The display will show the following indication...

Page 19: ...chart Those modes which have not been included have a lower information service output One the right hand side of the chart are the different unit step functions 64 QAM 2 3 64QAM 3 4 64QAM5 6 64QAM 7...

Page 20: ...the quality of the building s distribution network the better the transmission channel will be when transmitting signals Given that our transmission channel is better we can use the DVBS2 COFDM trans...

Page 21: ...remotely a Local control The Headend Management programme v2 13 or higher is required as well as a special cable provided with the programme that connects a PC serial port to the DVBS2 COFDM T0X PRGM...

Page 22: ...of 7 channels of DVBS2 COFDM T0X DVBS2 COFDM DVBS2 COFDM DVBS2 COFDM DVBS2 COFDM DVBS2 COFDM DVBS2 COFDM DVBS2 COFDM 5629 4512 75 ohm 4061 The diagram shows the assembly for the distribution of 7 cha...

Page 23: ...0X is located in warm place with a temperature higher than 45 C These ventilators will be installed on a tray that is fixed inside the cabinet fig 1 2 This way the ventilators will be able to extract...

Page 24: ...facilitate the ventilation of the units fig 5 It is very important that this process operates correctly therefore the following must be observed Do not open the side doors as this would cause the vent...

Page 25: ...t placement horizontal or vertical The maximum temperature permitted surrounding the highest cabinet is 45 C in both ways of placement horizontal or vertical way EXTRACTOR for forced ventilation must...

Page 26: ...lacement of the cabinets is strongly recommended hanging them as near to the floor as possible If the horizontal placement is impossible then vertical placement is allowed Respect the recommended mini...

Page 27: ...9 538 00 C31 554 00 31 533 00 C30 546 00 C31 554 00 C30 546 00 C30 546 00 C30 546 00 C30 546 00 H26 515 50 C30 546 00 C32 562 00 32 539 00 C31 554 00 C32 562 00 C31 554 00 C31 554 00 C31 554 00 C31 55...

Page 28: ...8 00 C59 778 00 C59 778 00 H55 718 50 C59 778 00 C61 794 00 61 713 00 C60 786 00 C61 794 00 C60 786 00 C60 786 00 C60 786 00 C60 786 00 H56 725 50 C60 786 00 C62 802 00 62 719 00 C61 794 00 C62 802 00...

Page 29: ...force at the time of purchase is applied Keep the purchase invoice to determine this date During the guarantee period Telev s S A complies with the guarantee by repairing or substituting the faulty e...

Page 30: ...DVBS2 COFDM 30...

Page 31: ...EN 31...

Page 32: ......

Reviews: