Timewave PK-232MBX, Руководство по эксплуатации, Страница: 109 / 231

PK-232 MBX – OPERATING MANUAL SIAM AND TDM OPERATION
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CHAPTER 10 – SIGNAL IDENTIFICATION AND TDM OPERATION
10.1 Overview
As you tune across the High-Frequency bands these days you find an ever increasing num-
ber of digital signals. These signals range from the simple Murray Baudot code, to ASCII and
even packetized data. With the large number of speeds, formats and shifts now in use, it is
difficult to say the least, to determine what kind of signal you are listening to. Even with a
knowledge of digital communications, it is still time consuming to set the communication pa-
rameters correctly.
SIAM stands for SI gnal Identification and A cquisition M ode, and allows a wide variety of
digital signals to be automatically analyzed so they can be easily copied with the PK-232.
SIAM will "listen" to a signal for a few seconds and then display the type of signal and its
speed to the user. The user can then decide whether or not to copy the signal, or simply go
on to the next.
SIAM makes the PK-232 more useful to the radio amateur and the Short-Wave Listener
alike. Whether tuning across 20 meters, or searching the Short-Wave bands, when you find
a signal SIAM will help you decide what it is, and tune it in without time consuming trial and
error.
10.2 SIAM Operation
When preparing to tune in a digital signal, the only decision the operator needs to make be-
fore entering the Signal analysis mode is whether the signal is narrow or wide shift.
The command WIDESHFT determines whether or not the filters in the PK-232 are set for
copying signals with a frequency-shift of greater than 200 Hz (WIDESHFT ON) or a shift of
200 Hz or less (WIDESHFT OFF).
Inside the Amateur bands most signals will be using 170 or 200 Hz shift and so WIDESHFT
should be OFF. Outside the Amateur bands most stations will be using a frequency shift of
more than 200 Hz and so WIDESHFT should be set ON.
10.2.1 Tuning in FSK Narrow and Wide Stations
Tuning in the Frequency Shift Keying (FSK) signal properly is critical to successful SIAM
operation. SIAM can only decode a signal properly if it is tuned correctly. Follow the tun-
ing procedure below carefully for the best results in tuning HF FSK stations.
o Make certain your HF receiver is either in LSB or FSK depending on your PK-232 set-
up.
o Turn any IF-Shift and Passband-Tuning controls to the Center or OFF position.
o Tune your receiver carefully across the band looking for the distinctive two tone
sound of an FSK signal.
o When you find a station, slowly vary VFO tuning knob on your receiver and look for
a display on the PK-232 tuning indicator like the one shown below.