User Manual

LBI-38636S
23
ALIGNMENT PROCEDURE
Alignment of the MASTR III base station was
performed prior to shipment. The factory assumed the
following characteristics:
1. There is no loss or gain for repeated audio
deviation.
2. If a remote exists, it is connected to the base
station through a telephone line with 10 dB of
loss.
3. The base station drives the line output at -10
dBm with nominal receive deviation.
The base station should deliver –10 dBm to the line
with a signal applied with 3kHz deviation. A –10 dBm
audio signal applied to the Station Line In should result in
transmitter deviation of 3 kHz.
These values may be altered by following one of the
alignment procedures as provided. For minor adjustments
you may want to adjust only one or two digital
potentiometers or leave the setting as set. In any case, it is
important to carefully examine the ALIGNMENT
DIAGRAM (Figure 15) which follows:
NOTE
It is a good idea to record the potentiometer
settings on paper, until you’re familiar with all
the digital potentiometer setting tools.
Test Equipment Required
The following test equipment is required to align the
MASTR III base station:
•
Audio Oscillator
•
AC Voltmeter
•
RF Signal Generator
•
Deviation Monitor
•
Handset or PC Computer (with diagnostic utility
TQ-0619)
Procedure
Terminate both the Line Input (T101-3,4) and Line
Output (T101-2,5) with a 600 ohm load. This step must be
completed for all parts of the alignment to ensure proper
level setting (Table 4).
1. Line In
•
Set Line Input digital potentiometer (Pot) LI
to 0.
Table 4 - Normal System Deviation
System Deviation
Standard (25 Hz kHz Bandwidth 3.0 kHz
NPSPAC 2.4 kHz
Narrow (12.5 kHz Bandwidth) 1.5 kHz
2. Channel Guard (GC)
•
If the station is not programmed for CG, set
CG Pot to 0.
For a station programmed with CG encode follow
these steps:
•
Execute a REMOTE PTT on the System
Module by flipping the REM PTT switch
on the front panel.
•
Adjust the CG Pot as needed (Table 5).
Table 5 - Channel Guard Deviation
Channel Guard
Deviation
Standard (25 Hz kHz Bandwidth 0.750 kHz
NPSPAC 0.600 kHz
Narrow (12.5 kHz Bandwidth) 0.500 kHz
•
Repeat for each channel.
•
Disable CG decode and encode for the
remainder of the station alignment.
3. TX Limiter
•
Preset the following digital potentiometer
values:
Repeater Gain (RG) 1023
Compressor Threshold (CT) 5000
Compressor Gain (CP) 1023
DSP Line In (DLI) 100
•
Apply a 1000 Hz tone, at the maximum
system audio level, across the 600 ohm load
termination to the Line Input.
This level is the secur-it level, and is
usually 0 dBm across 600 ohms, (775
mVrms). The "maximum system audio
level" is the absolute highest signal level
that will be present on the line and must be
10 dB higher than average voice audio level.
•
Execute a REMOTE PTT on the System
Module by flipping the REM PTT switch
on the front panel.
•
Adjust the TX Pot to maximum system
deviation (Table 6).