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Drake QM1000 Modular QAM Modulator User Manual

Page 5

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INTRODUCTION, SETUP, AND OPERATION

Introduction

The Drake® QM1000 QAM Modulator with

Upconverter is a professional quality modu-

lar digital headend component designed to

provide optimum performance with minimized

rack space requirements. This modulator

accepts a MPEG2 transport stream input in an

ASI serial format and is capable of providing

a QAM output with 64 or 256 constellation

points.

The modulator performs the forward error

correction (FEC) encoding according to ITU

J.83 Annex B. Annex B is referred to as

‘DigiCipher II®’. The front panel push wheel

selector and channel display allow the se-

lection of QAM RF Channel Output, and a

sliding Modulation Selector allows for setting

the QM1000’s QAM Output modulation mode

(a CW output mode option is also selectable

to allow measurement of the output level with

an analog signal meter). The output symbol

rate is set at 5.056941MS/S for 64QAM, and

5.360537MS/S for 256QAM. The maximum

RF output is +45dBmV nominal (+30dBmV

44MHz IF mode) and may be attenuated with

the RF Output Level Adjustment Dial located

on the front panel. This RF Output Level Ad-

justment Dial attenuates in 0.5dB increments

with a total range of 15dB.

NOTE: the 44MHz

IF mode is selected by setting the front panel

Channel Selector switches to 000.

NOTE:

The QM1000 requires the use of a separate

power supply and module chassis:

The power supply is the Drake PS8.

The chassis is the Drake DRMM12.

5

FRONT VIEW

Power LED

ASI LED

Channel Selector

(push wheel)

Modulation Selector

RF Output Level

Adjustment Dial

Chassis Removal

Handle

REAR VIEW

ASI Input Port

Power Supply Port

Interleaver Dip

Switch

RF Output Port