Controls and Connections
TVM450/S/TVM550/S/TVM550II/TVM550IIS
Owner’s Manual
Page 3-1
3 CONTROLS AND CONNECTIONS
Control/Connector Locations
The TVM-series have convenient control locations provide ease of operation.
Front Panel for Models with CMA60 Audio Module
Refer to Figure 3-1 for the following description:
1.
POWER –
Red LED (TVM450) or Green LED (TVM550 models). Indicates that
the unit is plugged into the AC power and is operational.
2.
VIDEO OVER MOD –
Red LED. Lights when the video depth of modulation
level exceeds 87.5 percent modulation.
3.
OFFSET –
Green LED. Lights when the selected channel has a prepro-
grammed FCC-assigned offset frequency. The light goes out when the OFFSET
switch (27) is in the OFF or AUTO position. See rear panel callout (27) for addi-
tional switch settings.
4.
RF OUTPUT –
Green LED. Lights when RF output is not muted, and when
the phase-locked loop (PLL) is locked on-channel. The RF output is con-
trolled by the CHANNEL SELECT switch (6) or during a power-up condition.
When this LED is off, the RF output is muted to –75 dBc, eliminating an un-
wanted output during a tuning sequence or powering-up condition.
5.
CHANNEL OUTPUT –
Red, dual-digit LED numeric display. Displays the
current channel number being output to the RF OUT jack.
6.
CHANNEL SELECT –
Rotary switch. Rotating this switch clockwise or
counterclockwise changes the channel number sequentially higher or lower,
respectively. When rotated to a different channel, RF OUT is muted for ap-
proximately four seconds. The RF OUTPUT LED goes out during this period.
7.
VIDEO MODULATION –
Potentiometer. Adjusts the video modulation level.
The center detent position is preset for an 87.5 percent depth of modulation,
with a 1.0 V peak-to-peak video input signal.
8.
VIDEO/AUDIO RATIO –
Potentiometer. The center detent position is cali-
brated for –15 dBc aural carrier output (maintained throughout the RF
LEVEL (9) range).
9.
RF LEVEL –
Potentiometer. Rotating clockwise or counterclockwise in-
creases or decreases RF OUTPUT level (+45 to +60 dBmV). It is recom-
mended that these units be operated at +58 to +60 dBmV.
10.
AUDIO DEVIATION –
Seven-segment LED bar display. Indicates the peak
aural deviation in percent. When the sixth bar of this display is lit, a repre-
sentation of 100 percent or 25 kHz peak aural deviation is present. The sev-
enth bar represents overdeviation and should light only occasionally. The bar
display is precalibrated with an internal 15 kHz low-pass filter for accurate
monaural or BTSC (L + R) indication.
