WAVECOM Decoder W74PC, W-PCI/e, W-CODE, W-CLOUD Manual V9.1.0
Transmission Modes
139
Tone Allocation
DIGIT
Hz
0
400
7
1477
1
697
8
1633
2
770
9
1800
3
852
A
1900
4
941
B
2000
5
1209
C
2100
6
1335
D
2200
7
1477
E
2300
Tone duration: 100ms.
CHINESE 4+4
Chinese 4+4 is a multi-carrier transmission mode. It consists of 8 carriers. They are 300 Hz apart, execpt
the 4
th
and 5
th
carriers, which are 450 Hz apart from each other.
Parameter
Value
Frequency Range
HF
Operation modes
Multi-carrier PSK
Modulation
DQPSK
Symbol rate
75 Bd
Shift
300 Hz between each carrier, 450 Hz between the two carriers in the middle
Receiver settings
LSB or USB
Input format(s)
AF, IF
Every carrier is DQPSK modulated with a symbol rate of 75 baud.
Wavecom Chinese 4+4 decoder uses Hadamard soft-decision decoding. During decoding the paramater
Confidence shows the error correction quality. A values above 95% means almost all errors are corrected.
However, this is just a qualitative measure.
The decoder can correct a center frequency error of up to +/- 30 Hz automatically. The user needs to
place the frequency cursor in this range. The user has to specify the polarity of the signal, i.e.,
NOR
(mal)
or
INV
(erse).
CHU
CHU is a radio station operated by the National Research Council of Canada.
It continuously broadcasts time information on 3330 kHz, 7850 kHz and 14670 kHz.
The information provided is the Gregorian year, Julian date, UTC hour, minute and second. Further infor-
mation is a leap second warning, DUT1, the difference between the International Atomic Time TAI and
UTC and the code for the Canadian daylight time indication.
