Drake QM1000 Modular QAM Modulator User Manual
Page 5
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