Drake digital TMQAMASI, TMQAM User Manual

1 TMQAM and TMQAMasi DIGITAL QAM MODULATORS

TM

12 POSITION RACK MOUNT POWER SUPPLY

TMQAM

QAM

MODULATOR

BIT RATE

19.327 M

ENTER

DUC550

asi

TMQAM

POWER
ERROR

MODULATOR

BIT RATE

3 5

19.327 M

GAIN

DUC860

TMQAM

QAM

ENTER

POWER
ERROR

MODULATOR

BIT RATE

19.327 M

3 5

CATV+100
CATV

GAIN

DUC550

asi

QAM

ENTER

TMQAM

POWER
ERROR

MODULATOR

BIT RATE

3 5

19.327 M

GAIN

DUC860

PS8

QAM

ENTER

POWER
ERROR

3 5

CATV+100
CATV

GAIN

POWER SUPPLY

FRONT PANEL CONTROLS AND INDICATORS 2

TMQAM

asi

QAM

F1

MODULATOR

BIT RATE

F2

19.327 M

F4

F3

ENTER

F3
F4

TMQAM

asi

MODULATOR

The R.L. Drake model TMQAM and TMQAM
modulators are professional quality modular
digital headend components designed to
provide optimum performance with minimized
rack space requirements. These modulators
accept an MPEG2 transport stream input in
either the SPI format or ASI serial format,
depending on the model, and is capable of
providing a QAM output with 16, 32, 64, 128,
or 256 constellation points.

The modulators perform the forward error
correction (FEC) encoding according to ITU
J.83 Annex A or Annex B. Annex A is referred
to as ‘DVB’ and Annex B is referred to as
‘DigiCipher II®’. The front panel push-buttons
and display provide full access to many other
parameters that can be set to match a
particular application.

The TMQAM model provides a choice of two
clock modes. In the ‘Auto’ mode, the output
clock rate is automatically locked to the
incoming data clock rate.

TMQAM MODULATOR

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Thus the output symbol rate can change if the
input data rate changes. The TMQAM
does not have an "Auto" selection. In the
‘Fixed’ mode, the desired output symbol rate is
programmed from the front panel. This rate
must be equal to or greater than the incoming
data rate. The output rate will be maintained at
the set rate and if the input rate is slower than
this rate, the TMQAM and TMQAM
null packets to make up for the slower
input rate.

The modulators have several test modes that
can be selected. In these modes, a
pseudo-random binary sequence stream is
substituted for the input source. This will
provide a modulated output without any
external input source.

A CW output mode is selectable to allow
measurement of the output level with an analog
signal meter.

The RF output is +30 dBmV. This IF output
can be connected to one of the DRAKE DUC
series of digital upconverters to provide an
output on a CATV or broadcast channel.

asi

will add

asi

model

F1 - LCD Display

Displays the modulator parameter and its
setting.

ENTER

F2 -

ENTER

Use the ENTER button to enter the adjust
mode or to save and load a new parameter
value. Hold for 2 seconds to enter the adjust
mode. After adjustment, press this button once
to load and save the value.

Figure 1

F3 - Left and Right Button

Use the Left and Right buttons to select the
parameter you desire to view or adjust.

F4 - Up and Down Buttons

Use the Up and Down buttons to adjust a
parameter value when in the adjust mode.
When not in the adjust mode, the UP button
displays the version number. The Down button
displays the incoming bit rate if the "AUTO"
clock mode has been selected.

3 REAR PANEL CONNECTIONS

INSTALLATION 4

R1

44 MHz

13

1

GND

IF OUTPUT

R3

POWER

+12 V

+5 V

R2

25

SPI LVDS INPUT

14

Figure 2 Figure 3

R1 - 44 MHz IF OUTPUT Connector

This is the modulator output. The level is
+30 dBmV.

R2 - 25 Pin SPI LVDS INPUT Connector

This is the MPEG2 transport stream input ­DVB Synchronous Parallel Interface. The levels
comply with low voltage differential signalling
specifications.

R3 - DC Power Connector

This is the power input connector. Connect to a
Drake PS8 or equivalent power supply,
(12 V @ 0 mA, 5 V @ 380 mA for the SPI
input version).

R4

44 MHz

IF OUTPUT

R5

ASI TRANSPORT

STREAM INPUT

R6

POWER

+12 V

GND

+5 V

R4 - 44 MHz IF OUTPUT Connector

This is the modulator output. The level is
+30 dBmV.

R5 - 75 Ohm, Type BNC Connector

This is the MPEG2 transport stream input; ASI
input, asynchronous serial interface.

R6 - DC Power Connector

This is the power input connector. Connect to a
Drake PS8 or equivalent power supply,
(12 V @ 0 mA, 5 V @ 500 mA for the ASI
input version).

CONNECTIONS AND CONTROLS

All connections to and from each modulator are
made through the rear panel. Refer to Figure 4
for correct cable and wiring connections.

POWER
SUPPLY

90-260 VAC

DC OUTPUTS X 8

AC POWER

CORD

12V GND 5V

IF IN

POWER

RF OUT

QAM MODULATOR

UNITS

IF IN

44 MHz

IF OUTPUT

POWER

POWER

SPI LVDS INPUT

RF OUT

TO QAM

DISTRIBUTION

TMQAM OPERATION AND SETUP

The TMQAM provides user access to many
parameters of the modulator so that it can be
setup to precisely match the requirements of
the system.

1) To VIEW parameter settings only – no
adjustment:

Press either the left or right arrow buttons to
scroll through each parameter page. The
parameter is listed on the first line of the display
and the present setting will be displayed on the
second line. After viewing, press the left or right
arrow button again to advance to the next
parameter. After viewing, the display will
time-out and return to the output baud (BD)
rate/symbol rate page.

RACK MOUNTING

Adequate ventilation is very important in
multichannel installations. Units should be
spaced apart by at least one panel height
wherever possible, and some air movement is
mandatory in enclosed rack cabinets.
Excessive heat will shorten component life and
modulator performance will be degraded
without proper cooling.

DUC550 OR DUC860

UPCONVERTERS

44 MHz

IF OUTPUT

POWER

IF IN

POWER

RF OUT

SPI LVDS INPUT

44 MHz

IF OUTPUT

POWER

IF IN

POWER

RF OUT

SPI LVDS INPUT

FROM SATELLITE

DEMODULATOR OR

OTHER LVDS DATA

Figure 4

STREAM

2) To ADJUST or change parameter settings
or for initial set up, follow these steps:

Press and hold the enter button for 2 to 3
seconds until the display begins to flash. Press
the left or right arrow button to scroll to the
desired parameter. Now press the up or down
arrow button to adjust the parameter value.
Note that no change is made at this point until
the new value is loaded and saved. When the
value is adjusted to the value required, press
the enter button again. This will load and save
the new value until this procedure is repeated.

SPI LVDS INPUT

44 MHz

IF OUTPUT

POWER