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4 cmmb modulation settings – DekTec DTC-300 StreamXpress User Manual

Page 28

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DTC-300-SP – StreamXpress

USER MANUAL

28

Variable

Type

Description

Details Diag

Modulation

Modes

Drop

down

Select if the modulator is using 8-VSB or 16-VSB

#1

1

Sideband

Filters

Drop

down

Select the number of taps for the sideband filter

#2

2


#1 Modulation Modes:
There are 2 modes defined by the ATSC standard 8 and 16-VSB. 16VSB was notably intended to be

used for ATSC digital cable, but QAM has been chosen as the cable industry standard instead. 8VSB

should be used as default.

#2 Sideband Filter:
These setting allow choosing the number of taps for the sideband filters. Changing the sideband

filters changes the shape of the RF envelope. The default value is 32 taps. Note that settings above

32 should be avoided as it will cost an excessive amount of CPU cycles to the PC with no real gain

in the modulation.

3.5.4 CMMB Modulation settings

If the DekTec Adaptor is licensed to support the CMMB modulation, the user can select the CMMB

modulation and change its parameters.
NOTE: The CMMB modulation does not accept direct transport streams. It requires the use of the

CMMB multiplexed file.
NOTE: The CMMB modulation is used both in the Satellite band and the UHF/VHF band. DekTec

StreamXpress only support CMMB in the UHF/VHF band.

Variable

Type

Description

Details Diag

Channel

Bandwidth

Drop

down

Select the modulator bandwidth between 2Mhz and 8Mhz

#1

1

TxID

Field

Select a number for Transmitter Identity (128-256)

#2

2

Area ID

Field

Select a number for Area Identity (0-127)

#3

3

1

2