Wavecom W74PC V8.7.0 - Manual (Page 152)

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Transmission Modes WAVECOM Decoder W74PC, W-PCI/e, W-CODE, W-CLOUD Manual V8.7.0
CIS-50-50
CIS-50-50 is very similar to CIS 36-50, but uses different baud rates and shifts.
Parameter Value
Frequency range VLF, HF
Operation modes Simplex
Modulation FSK
Symbol rate 50 and 100 Bd
Shift 85, 125, 250 and 500 Hz, variable 50-3500 Bd
Receiver settings DATA, CW, LSB or USB
Input format(s) AF, IF
Idle dot reversals are transmitted at 50 Bd, followed by traffic in 50 baud (more rarely in 100 Baud).
All traffic is encrypted.
A message begins with a bit synch sequence and a start-of-message preamble. Message data is sent with
a 7-bit, 3:4 ratio alphabet, and ends with an end of transmission sequence containing at least 4 end-of-
transmission characters.
The length of a message is variable. If a transmission contains more than one message, the start of mes-
sage sequence is left out between messages.
Occasionally traffic with call signs in FSK CW is transmitted.
CLOVER-2
CLOVER-2 is an adaptive modulation system with ARQ and FEC (broadcast) modus. It uses Reed-Solomon
(RS) coding to achieve a remarkable performance even under poor HF propagation conditions.
Parameter Value
Frequency range HF
Operation modes Half-duplex ARQ
Modulation PSK2A, PSK4A, PSK8A, PSK16A, ASK2PSK8, ASK4PSK16, 2DPSK2A
4 tones
Symbol rate 4 x 31.25 Bd
AFC ±200 Hz, with max. single step ±10 Hz.
Receiver settings DATA, CW, LSB or USB
Input format(s) AF, IF
Additional Info ITA-5, Optional Mode
Data is modulated onto four tones spaced 125 Hz. The modulation rate of each tone is 31.25 Baud. The
supported modulation techniques include binary phase-shift keying (PSK2A), quaternary PSK (PSK4A), 8-
PSK (PSK8A), 16-PSK (PSK16A), binary amplitude-shift keying combined with 8-PSK (ASK2PSK8), quater-
nary ASK combined with 16-PSK (ASK4PSK16), and two-channel diversity binary PSK (2DPSK2A).
CLOVER-2 frame includes CCB (Clover Control Block) and data block with variable lengths and modula-
tions. Each data block is displayed immediately after receiving. The decoder status indicates “TRAFFIC”.
When a CCB is received, the decoder status switches to “IDLE”. The content in a CCB is displayed only
when call sign or text is available. The call sign is displayed in the status line and the short text is dis-
played in the main window.
RS coding is utilized to correct transmission errors. Four coding levels (called RS Efficiency) are specified,
which allow for more or less error correction within a block. The percentages in the following list of coding