User's Manual

300-Watt Digital UHF Transmitter Chapter 5, Detailed Alignment Procedures
DT830A, Rev. 1 5-8
of that tray until a peak is reached or
until the end-of-travel is achieved. If the
end-of-travel is reached, repeat the
above procedure, replacing the 2-inch
length of cable with a 4-inch length of
cable. Once a peak is reached, move the
phase control that is full CCW up two
turns and repeat it using the phase
control on the other tray. This allows
both trays to have some range of
adjustment.
5.3 (A19) 8-VSB Digital Modulator
(1075164; Appendix C)
The connections to the 8-VSB modulator
are made through the rear panel except
for the IF sample output, which is made
through the front panel. These
connections are shown in Table 5-3.
Table 5-5. 8-VSB Modulator Connections
REFERENCE LABEL FUNCTION
J1 IF O/P
IF output from the modulator; nominal output power level is
–18 dBm
J2
10 MHz
I/P
10 MHz reference input; signal level is 0 to +3 dBm
J3 MPEG I/P
SMPTE 310M input; only used when the MPEG source is in
accordance with the SMPTE 310M specification
- ECL
37-pin D connector used to interface to serial ECL MPEG
signals. The pinout of this connector is defined in the setup
and operation procedures in Chapter 2 of this manual. This
input is used only when SMPTE 310M signals or serial TTL
signals are not provided.
- TTL
25-pin D connector used to interface to serial TTL MPEG
signals. The pinout of this connector is defined in the setup
and operation procedures in Chapter 2 of this manual. This
input is used only when SMPTE 310M signals or serial ECL
signals are not provided.
-
IF
SAMPLE
Provides a front panel sample of the IF output
- PORT A
9-pin, D, RS-232 interface used to load the preset
coefficients and is also used as an interface to the
demodulator when ADAPTIVE is implemented.
- PORT B
9-pin, D, RS-232 interface used to monitor the operation of
the modulator via a laptop computer.
- REMOTE
15-pin, D interface that provides hard-wired indications of
the front panel LEDs. All of the lines are active low. The
available signals are:
• Pin 6 – MPEG present
• Pin 7 – Reference present
• Pin 8 – Ref PLL locked
• Pin 9 – Power present
• Pin 5 – Ground