User Manual

LBI-38636S
25
5. Line Input Sensitivity and Compression
•
If not a remote station, set the DSP Line In
DLI Pot to 0.
•
If a remote station, do the following:
Apply a 1 kHz tone at the average voice
audio level across 600 ohms to the line
input. (This level is the function tone level,
and is usually -10 dBm across 600 ohms, or
245 mVrms. This level MUST be 10 dBm
below the "maximum system audio level"
even if your actual secur-it tone and function
tone are at the same level.)
•
Execute a REMOTE PTT on the System
Module by flipping the REM PTT switch on
the front panel.
•
Adjust the DSP Line In DLI Pot for 60% of
maximum system deviation if operating with
compression. (Table 9).
Table 9 - Deviation For Setting Line In Pot With
Compression
Deviation For Setting
Line In Pot With
Compression
Standard (25 Hz kHz Bandwidth 2.8 kHz
NPSPAC 2.2 kHz
Narrow (12.5 kHz Bandwidth) 1.4 kHz
•
If no compression is desired, set DLI pot to
60% of maximum system deviation (Table
8).
•
If compression is desired, adjust the DLI Pot
for 60% of maximum system deviation
(Table 8).
•
Increase the audio input level to the
maximum system audio level. (This level is
the secur-it level, and is usually 0 dBm
across 600 ohms, or 775 mVrms. This level
must be 10 dB higher than the average voice
audio level.)
•
Adjust the Compressor Threshold CT pot for
desired compression deviation level (Table
10).
Table 10 - Deviation For Setting Compressor
Threshold Pot
Deviation For Setting
Line In Pot With
Compression
Standard (25 Hz kHz Bandwidth 4.0 kHz
NPSPAC 3.2 kHz
Narrow (12.5 kHz Bandwidth) 2.0 kHz
6. Line Out
•
If not a remote station, set the Line Out LO
Pot to 0.
•
If the station is a remote station, apply an
"on Channel" RF signal modulated with a 1
kHz tone at 60% of system deviation to the
receiver. (60% of system deviation is
usually 3 kHz.)
•
Adjust the Line Out LO Pot for the desired
output level as measured across 600 ohms.
The line out level must never rise above 7
dBm, as measured across 600 ohms.
•
Re-enable Channel Guard decode.
7. DSP cancellation
•
If the station is a 4 wire station, set the DSP
Line Cancellation DC Pot to 0. If the station
is 2 wire, do the following:
•
Apply a RF signal to the receiver modulated
by a 1000 Hz tone at 60% of rated system
deviation and monitor the remote’s Line
Out. The level of the Line Out should be
between +7 dBm and -19 dBm.
•
Put the System module on an extender card
and meter TP1 on the DSP board. On
stations with Group 6 or later T/R shelf, the
TPI signal can be observed at J5-28A on the
backplane. An oscilloscope may be more
helpful than an analog meter. Adjust the
DSP Cancellation DC Pot for a null at TP1.
8. Tone Remote timing
You must have PC Programmer for base stations,
version 9.0 or later, to affect the timing of Tone
Remote Decoding.
If you have two wire tone remote, do the
following:
•
In the timing screen of the option screen,
ENABLE Timed Tone Remote. The
default values of 100ms and 150ms will
appear for Secur-it minimum time and
Secur-it maximum time. Change these
values as your system requires.