DRAKE DQT861 Gebruiksaanwijzing - Pagina 11

Blader online of download pdf Gebruiksaanwijzing voor {categorie_naam} DRAKE DQT861. DRAKE DQT861 15 pagina's. Digital to qam transcoder; multiplexing qam modulator

Pagina afdrukken

The third option is the BASIC MGT, VCT choice. When this

selection is made, the DQT1000 or MQM1000 will build its

own MGT and VCT tables from the incoming streams even

if one or both of the streams do not contain these tables.

This solution should satisfy all types of set top boxes but

will not provide any EIT table program guide information.

The STT and RRT tables from the source are passed

through unchanged in the ENABLED mode and filtered out

in the other modes.

VCT TABLE: This menu is only available when ENABLED

or BASIC MGT, VCT has been selected in the previous

PSIP menu. You may select the TVCT - TV channel table or

CVCT table for CATV. Usually the TVCT choice must be

selected for ATSC input signals.

MAJOR CHANNEL: This menu is not available if PSIP is

disabled. When ORIGINAL is selected, the major channel

number indicated in the output tables will be that sent by

the original broadcaster. If OUTPUT CHANNEL is selected,

the major channel number will be set to the channel

number of the DQT1000 RF output channel. This setting

will determine how a channel number is displayed on a

consumer TV if the TV is tuning the output of the DQT1000

without a cable box. When a cable box is used, it usually

does not require or use this information.

QAM MODE: This menu allows the user to set the modula-

tion type for the output. Choices range from 16-QAM

through 256-QAM. A suffixes indicate DVB compliant FEC

and the B suffixes indicate DigiCipher II FEC encoding.

Note that when using the DQT1000 or MQM1000 in the

multiplex mode, the output QAM mode usually must be

256-QAM. For CATV systems using DigiCipher II, select the

QAM-256B mode. For DISH Network QAM distribution or

other DVB systems using DVB set tops, choose the QAM-

256A mode.

When used for a single input processing function, choose

the output mode accordingly from any of the available

options that will provide a high enough data rate.

QAM SYMRATE: This menu allows selection of the output

QAM baudrate or symbol rate. Set as required by the set

top box. When multiplexing two ATSC input signals, in

DigiCipher II, 256-QAM CATV systems, this is usually

5.3606 Ms/s. In DVB systems, the rate would be 5.264

Ms/s. In any case, the rate must be high enough to provide

Setup and Programming, continued

a data bitrate of at least 38.81 Mbps (do not confuse this

with the symbol rate). If the set top box requires a fixed

higher rate, this may be manually set.

INTERLEAVER: Sets the QAM modulator interleaver.

Choose among the available selections based upon your

system / set top box requirements. For typical 256-QAM.

DigiCipher II CATV systems, I128, J1 is the most com-

monly used interleave setting but many other choices are

available. This menu does not appear in the adjust mode if

the QAM mode is A (DVB) as there is only one choice in the

DVB standard. When not in adjust mode, this screen will

display the setting in QAM - A modes as well.

OUTPUT FORMAT: For normal operation, select NORMAL.

For system level set up, choose CW to provide a CW

carrier at the center frequency of the output channel for use

in leveling a system when a QAM power meter is not

available. To disable all RF output, select STANDBY. In the

CW mode, the CW carrier can be measured on a spectrum

analyzer without a need to apply a bandwidth correction or

it can be measured with an analog meter tuned to channel

center. The CW power measured will equal the channel

QAM power when the modulator is returned to NORMAL

output mode. Usually QAM signals are set 5 dB to 10 dB

below analog NTSC channels when balancing a system.

The PRBS modes provide a pseudo random binary

sequence output test signal for use in laboratory testing.

OUTPUT CHANMAP, OUTPUT CHANNEL: Select the desired

EIA CATV channel output using these two menus.

RF OUT: Select the desired RF output signal level. The

available range is between 45 dBmV and 62 dBmV,

selectable in 0.5 dB steps. The output accuracy is ± 1 dB.

UNIT ID: Select the desired unit identification number when

connecting the 'RS232 IN' connector to a PC or modem for

remote control using Drake Remote Control Software.

Numbers 1 thru 63 may be used. If zero (0) is selected,

the PC will ignore the unit.

RS232 BAUD RATE: This setting determines the baud rate

at which the DQT1000 or MQM1000 communicates with

the remote PC. Settings available are 2400, 4800, 9600

and 19,200. All unit 'daisy chained' to the remote PC or

modem must be set to the same baud rate.