Wavecom W74PC V8.7.0 - Manual (Page 258)

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Transmission Modes WAVECOM Decoder W74PC, W-PCI/e, W-CODE, W-CLOUD Manual V8.7.0
In ASCII ASYNC (7 data bits and no stop bit) mode, the bit stream is correlated with another ASYNC struc-
ture, i.e., one start bit (0) and 7 data bits. The 7 data bits are displayed LSB first. In addition to the EOM
pattern, the display will stop if more than 300 NULL characters are received.
In ASCII SYNC mode, each 8 bits (LSB first) represent one ASCII character. The display will stop when ei-
ther the EOM pattern was recognized or more than 20 NULL characters have been received.
Tuning the decoder
The decoder can process signals in both SSB settings: USB and LSB. The sideband is selected by toggling
the Polarity field of the display: NOR will select USB and INV will select LSB.
The center frequency of the decoder is set to the default value of 1800 Hz, but can be adjusted within a
range from 800Hz to 2400Hz. Small frequency deviations are automatically tracked and compensated dur-
ing the decoding. By using the bar graph, any remaining frequency difference can be compensated by fi-
ne-tuning of the receiver frequency or by adjusting the center frequency of the decoder.
In the Confidence field, the quality of decoding can be observed. A well recognized stream is determined
by a confidence value being stable and greater than 95 (i.e., 95% of the message is correct).
STANAG-4529
STANAG-4529 is specified by the NATO (North Atlantic Treaty Organization) Military Agency for Standardi-
zation in "Characteristics of Single Tone Modulators / Demodulators for Maritime HF Radio Links with
1240Hz Bandwidth" (14. December 1995).
Parameter Value
Frequency range HF
Operation modes PSK, Broadcast/Simplex FEC
Modulation 8-PSK
Symbol rate 1200.0 Bd
Center frequency 1700 Hz
Receiver settings DATA, CW, LSB or USB
Input format(s) AF, IF
Additional Info 16 Bit redundancy
The modulation technique used in this mode consists of phase shift keying (8-PSK) of a single tone sub-
carrier that is selectable in 100Hz steps from 800Hz to 2400 Hz, with a default value of 1700 Hz.
The modulation speed (symbol rate) is always 1200 Bd. Through the use of different M-PSK modulation
formats and FEC (Forward Error Correction) coding rates, serial binary user information (raw data) ac-
cepted at the line side input can be transmitted at different user data rates.
STANAG 4529 single tone waveform has the following format characteristics which may be selected from
Options | Frame Format...
Baud Rate User data rate (bps) Bits per symbol (M-PSK) FEC coding
rate
Interleaver
1200 1200 3 (8-PSK) 2 / 3 SHORT or LONG
1200 600 2 (QPSK) 1 / 2 SHORT or LONG
1200 300 1 (BPSK) 1 / 2 SHORT or LONG
1200 150 1 (BPSK) 1 / 4 SHORT or LONG
1200 75 1 (BPSK) 1 / 8 SHORT or LONG
1200 1800 3 (8-PSK) uncoded ZERO
1200 1200 2 (QPSK) uncoded ZERO