Installation and Operation
TVM450/S/TVM550/S/TVM550II/TVM550IIS
Owner’s Manual
Page 4-7
RF Level Adjustment
1. Connect a spectrum analyzer to the RF OUTPUT jack located on the
modulator rear panel.
2. Rotate the RF LEVEL adjustment until the desired output level is achieved.
The RF output is adjustable to +60 dBmV, but the unit should be operated at
+58 to +60 dBmV for best results.
FCC Offset Switch
The FCC OFFSET switch provides the flexibility to:
•
Select the OFF position to turn the automatic offset feature off, or to
remove any offset frequencies.
•
Select one of four manual offset frequencies, as shown in Figure 4-4.
•
Select the AUTO position (TVM450 only) to allow the read-only memory
(ROM) or PROM (programmable ROM) to select the offset as pro-
grammed for each channel.
9038
Figure 4-4. FCC Offset Switches
CAUTION
Care must be taken when using the FCC OFFSET switch to select a man-
ual offset frequency (TVM450 only). If a channel is selected that has an
FCC-assigned offset and the FCC OFFSET switch is set to any of the
manual offset frequencies, the actual offset frequency is not as selected.
For instance, if the FCC-assigned offset frequency in ROM is –12.5 kHz
and a manual offset frequency of –12.5 kHz is selected, the resultant offset
frequency will actually be –25 kHz.
On the other hand, if the FCC-assigned offset frequency is –12.5 kHz and
an offset frequency of +12.5 kHz is manually selected, the resultant offset
frequency will be 0 kHz (or no offset). See Table 4-1 to make sure the cho-
sen FCC OFFSET switch manual position is correct.
A TVM550-series unit assigns only the frequency selected.
