Cable AML ITX21-100, Руководство по установке и обслуживанию

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Indoor Broadband Transmitter – ITX21-100
IM4030013-1 Rev –
13
4.0 OPERATION
The ITX21-100 transmitter requires no adjustments when used in the configuration
recommended in the Data Manual. To properly operate the transmitter, simply apply the
required AC power and input signal. The ITX21-100 transmitter can be equipped to
operate on either 120 or 240 VAC at 50 or 60 Hz. This option is specified by customer
request, and each unit is shipped according to these specifications.
4.1 Output Level Setting
The output power for each ITX21-100 Transmitter Unit depends entirely on the input level.
If the input level at VHF is higher than the recommended value, both the output power
and the CTB (Composite Triple Beat) distortion will increase. For every one dB of higher
input level there will be one dB of higher output power and two dB higher distortion.
CONSEQUENTLY, IT IS NOT RECOMMENDED TO CHANGE OR ADJUST THE
TRANSMITTER OUTPUT LEVELS UNLESS THERE ARE SIGNIFICANT CHANGES IN
THE NUMBER OF INPUT CHANNELS OR OTHER SYSTEM PARAMETERS.
A Microwave Power Meter or Spectrum Analyzer is required to set the Output Level. It
should be connected to the transmitter output monitor connector on the front panel.
The output level can then be set by adjusting the VHF Processor Module's level set
attenuator labeled "VHF ADJ" for the required output level required by the system design.
The adjusting screw is shown in Figure 7. If a power meter is not available, the
transmitter output monitor reading can be used in conjunction with a table provided with
the transmitter performance data sheets provided in the Data Manual.
Observe the output of the transmitter with the spectrum analyzer. Using the "VHF ADJ”
set the channel levels to the desired level. An individual channel that is out of line with the
others must be adjusted at its source.
P/N 42104-002
VHF
ADJ
VHF IN
VHF OUT
VHF LEVEL
ADJUSTING
SCREW
Cable AML
Figure 7. Output Level Adjustment.