Timewave PK-232MBX, Руководство по эксплуатации

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PK-232 MBX – OPERATING MANUAL SIAM AND TDM OPERATION
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TDM is an immediate command that places the PK-232 in the TDM receive mode. TDM
stands for Time Division Multiplexing, also known as Moore code and is the implementation
of CCIR Recommendation 342. The following describes the TDM mode and commands in de-
tail.
10.4.1 TD-M Parameters
If you are using an AEA PAKRATT program, follow the instructions in the program manual
to enter the TDM mode.
If you are using a terminal, simply type TDM from the Command Mode followed by the
<Enter> key to enter the TDM mode. The PK-232 responds by displaying the previous
mode:
Opmode was PAcket
Opmode now TDm
10.4.2 Monitoring TDM Signals
The TDM command forces bit phasing; do this when changing frequency to another TDM
signal. This is also useful when the PK-232 synchronizes on the wrong bit in the character
stream, which is likely on a signal which is idling. TDM stations idle MOST of the time, so
you may have to leave the PK-232 monitoring for an hour or two before any data is re-
ceived.
TDM signals allow multiple data streams to share the same RF channel. The PK-232 can
receive either 1, 2 or 4 channel TDM signals. When monitoring 2 or 4 channel TDM, the
TDCHAN command allows you to select which channels will be displayed. The TDCHAN
command takes an argument from 0 to 3 to allow any one of the four channels of a
4channel TDM station to be monitored.
TDM signals operate at different data rates. The TDBAUD command allows any data rate
from 0 to 200 baud to be selected, but only the values in the following list are valid.
1-channel: 48, 72, 96
2-channel: 86, 96, 100
4-channel: 171, 192, 200
10.4.3 Where to Find TDM Signals
We have heard TDM signals on the following frequencies which should be used as a start-
ing point when looking for TDM signals.
9.125.9 LSB 11.246.5 USB 12.061.7 USB 14.623.3 USB
14.956.7 USB 18.983.6 USB 19.101.9 LSB 19.647.4 LSB
The above signals were using several different shifts. Remember to set WIDESHFT for the
frequency shift of the signal you are tuning.