Wavecom W61PC V7.5.0 - Manual (Page 215)

WAVECOM Decoder W61PC/LAN Manual V7.5 Transmission Modes  205
Note: In contrast to PSK-31 these modes do not use DQPSK modulation.
Tuning a PSK-63F and PSK-125F Signal
After launching the mode, the first step is to look for a valid PSK-63F or PSK-125F 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 precisely set. The adjustment pre-
cision of the center frequency is very important and directly influences the performance of the
decoding.
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 be-
tween the tracked and the adjusted center frequency is too large, the center frequency should be correct-
ed. Carrier tracking only works over a range of DBPSK center frequency ± 8 Hz.
Hence adjustment of the center frequency must be accurate.
In contrast to PSK-31, this mode does not use DQPSK modulation.
PSK-AM
PSK-AM is a very narrow-band and reliable amateur mode developed by F6CTE. The aim of this experi-
mental slow mode is to allow chat communication between hams.
Parameter Value
Frequency range HF
Operation modes Simplex
Modulation DBPSK
Symbol rate 10, 31.25 and 50 Bd
Receiver settings DATA, CW, LSB or USB
Input format(s) AF, IF
Additional Info 14.075 MHz
PSK-AM is similar to PSK-31, but uses its own fixed length 8 bit alphabet with a 5:3 ratio. Each character
is repeated 5 positions later. This diversity in time allows the correction of an invalid character.
Bitstream:
D(x) R(x-2) D(x+1) R(x-1) D(x+2) R(x) D(x+3)
D(x): character
R(x): repeated character
PZVEI
The entire call number is transmitted by consecutive tones in decade sequence. When two identical digits
are to be transmitted consecutively, then an eleventh frequency is used as a repetition identifier.
Parameter Value
Frequency range VHF/UHF
Operation modes Analogue Selcal
Modulation FM, SUB tone
Receiver settings FM, BW = 12 kHz
Input format(s) AF, IF