Operation; Tvm450/Tvm550/Tvm550Ii - Standard Communications TVM Series Owner's Manual

EXTERNAL BTSC – A baseband 600 ohm audio signal, –10 to +10 dBm peak pro-
gram (0 dBm L + R optimum), can be connected to the rear panel screw terminals. In
this configuration, the rear panel Audio switch should be set to BTSC. This setting
turns off the internal pre-emphasis and recalibrates the seven-segment audio indicator
bar display for a BTSC input mode. (Note: the front panel BTSC LED will light.)
•
A 4.5 MHz FM subcarrier from +30 to +60 dBmV (+35 dBmV optimum)
can be inserted into the rear panel 4.5 MHz IN connection. The rear panel
4.5 MHz INT/EXT switch should be in the EXT (external) position. This
defeats the internal 4.5 MHz signal and reroutes the 4.5 MHz subcarrier
path. (Note: the front panel BTSC LED will light.)
•
A 41.25 MHz FM subcarrier, +25 dBm can be inserted at the rear panel
aural IF LOOP IN. The rear panel 4.5 MHz INT/EXT switch should be in
the EXT position. This defeats the internal 4.5 MHz signal. (Note: the front
panel BTSC LED will light.)
INTERNAL CSG60 BTSC – The TVM450S and TVM550S modulators have a
built-in CSG60 BTSC Stereo Generator for integrated BTSC/Modulator opera-
tion. At the rear panel, a Left/Right baseband audio signal, –10 to +10 dBm peak
program (0 dBm optimum), balanced 600-ohm signal, can be inserted. This input
can be triggered by connecting the rear panel CONT (Control) and GND
(Ground) screw terminals for commercial insertion. When triggered, the
Left/Right inputs are disconnected and the Mono audio signal is bridged into the
Left/Right audio path, thus maintaining the BTSC spectrum.
INTERNAL DSG2000BD – The TVM550IIS modulator has a built-in DSG2000BD
digital stereo module that provides ultraclean stereo. Similar in operation to the
CSG60, this unit allows direct output of stereo signals. It can also be fitted with AGC
and SAP audio.

OPERATION

Refer to Figure 3-1 for control locations.

TVM450/TVM550/TVM550II

Channel Selection
1. Rotate the CHANNEL SELECT switch until the desired channel number is
displayed on the CHANNEL OUTPUT numeric display.
The RF output is muted while the CHANNEL SELECT switch is rotated,
until an internal phase lock is achieved.
2. Rotating the CHANNEL SELECT switch clockwise (CW) increments the
channel number, and rotating this switch in a counterclockwise (CCW) di-
rection decrements the channel number.
TVM450/S/TVM550/S/TVM550II/TVM550IIS
NOTE
Owner's Manual
Installation and Operation
Page 4-3