WAVECOM Decoder W74PC, W-PCI/e, W-CODE, W-CLOUD Manual V9.1.0
Transmission Modes
195
Waveform
Burst duration
Preamble
Payload
BW2
640 + (400 * n) ms,
1536 + (960 * n) PSK symbols,
n = 3, 6, 12, or 24
26.67 ms, 64 PSK symbols
1881 * n bits
BW3
373.33 + (13.33 * n) ms,
896 + (32 * n) PSK symbols,
n = 64, 128, 256, or 512
266.67 ms, 640 PSK symbols
8 * n + 25 bits
BW4
640.0 ms, 1536 PSK symbols
None
2 bits
The data in the different burst waveforms is used for different purposes:
BW0 is used for 3G-ALE PDUs (Protocol Data Unit)
BW1 for traffic management PDUs and HDL (High-rate Data Link Protocol) acknowledgement PDUs
BW2 for HDL traffic data PDUs
BW3 for LDL (Low-rate Data Link Protocol) traffic data PDUs
BW4 for LDL acknowledgement PDUs
The MIL-188-141B decoder processes the waveforms BW0, BW1, and BW4 only to their final stage, i.e.,
displays the user data bits (after deinterleaving and FEC decoding). The configuration (number of data
packet, FEC encoding and interleaver) of BW2 and BW3 is negotiated during the peer-to-peer communica-
tion, e.g., between two modems. These two waveforms can not be decoded to their final stage. For the
waveform BW3, the decoder just demodulates and display the bits. The “Confidence” for BW3 is the aver-
age value of each demodulated symbol over the whole frame.
The decoder displays the payload data of BW0 and BW1 in
BINARY, HEX
,
ASCII ASYNC
,
ASCII ASYNC
(7 data bits, 0 stop bit)
and
ASCII SYNC
formats selected from
Options/Message Type
.
In the
HEX
mode the payload data is displayed as it is, MSB first.
In the
ASCII ASYNC
mode the payload data is displayed as ASCII character, i.e., one start-bit (0), 8 da-
ta-bits (one ASCII character) and at least one stop-bit (1). The 8 data-bits are LSB first. The display is
stopped when 300 NULL (all zero in 8 data-bits) characters are received or if the async data structure is
violated more than 80 times.
In the
ASCII ASYNC (7 data bits, 0 stop bit)
the data is displayed in a similar way – one start bit (0),
7 data bits (LSB first) and no stop bit. Also the display terminates when more than 300 NULL characters
occur or the async data structure is violated more than 80 times.
In the
ASCII SYNC
mode the payload data is segmented into 8-bit (LSB first) ASCII characters and dis-
played.
The waveform BW4 has only 2 bits payload data, they are displayed in HEX format (MSB first).
Tuning the decoder
The decoder processes the signal in both SSB settings: USB and LSB. This can be selected with
Polarity
in the menu: NOR means USB and INV means LSB signal.
MIL-M-55529A NB/WB
MIL-M-55529A is an asynchronous FSK system and is based on ASCII. No error detection or error correc-
tion is implemented.
Parameter
Value
Frequency range
HF
Operation modes
Broadcast
Modulation
FSK
Symbol rate
50,75, 100 or 110 Bd
