Tuning A Psk-31 Signal With W51Pc Or W40Pc - Wavecom W40PC Manual

The bandwidth of the spectrum can be switched between 500 Hz, 1000 Hz, 4000 Hz and 24000
Hz. The upper and lower frequency boundaries of the signal is the selected with the right and
left cursors. With the center cursor, the center frequency may be set more precisely set The
precision of the center frequency is very important and directly influences the
performance of the decoding.
To transfer these values to the demodulator, let the cursors remain active and switch directly to
the PSK-31. The "Center" field then shows the adjusted center frequency.
To ensure, that the system can handle drifting signals or a coarsely adjusted center frequency,
"AFC" may be enabled in the "Demodulator" menu. The carrier tracking function is now
activated If the deviation between the tracked and the adjusted center frequency is too large,
the center frequency should be corrected. The carrier tracking only works over a range of:
Hence adjustment of the center frequency must be accurate.
The tuning display indicates, if a DBPSK or a DQPSK signal is being received. Two bars
mean DBPSK, four bars DQPSK. The demodulator must be adjusted accordingly.

Tuning a PSK-31 Signal with W51PC or W40PC

After launching the mode, the first step is to look for a valid PSK-31 signal in the spectrum. It
is possible that within a bandwidth of 4 kHz more than on station is working.
The bandwidth of the spectrum can be switched between 500 Hz, 1000 Hz, 4000 Hz and 24000
Hz. After that with the left cursor the lower limit and with the right cursor the upper boundary
of the signal may be selected. Using the center cursor, the center frequency may be more
178 • Transmission Modes
•
DBPSK Center ± 8 Hz
•
DQPSK Center ± 4 Hz
WAVECOM Decoders v6.15 W40PC, W41PC, W51PC