Wavecom W-SPECTRA (Automatic Monitoring System) V1.1.0 - Manual (Page 180)

170

Transmission Modes WAVECOM Monitoring System W-SPECTRA, W-SPEED Manual V1.1.0
Parameter Value
Frequency range L-Band/C-Band
Operation modes Inm-mM (Forward NCS and LES Msg Chnl)
Forward:
6 kbps DPSK, NCS TDM
8 kbps OQPSK, LES Voice SCPC, LES Low Speed Data
64 kbps QAM16, High Speed Data SCPC (ISDN)
Return:
3 kbps DPSK, Slotted Aloha, TDMA,
8 kbps OQPSK SCPC
64 kbps QAM16 SCPC (ISDN)
Required SNR >15 dB (20 dB recommended)
Input format(s) IF
In idle mode all mobile stations listen to the NCS (Network Control Station) common TDM channel, which
carries signaling information. When a mobile station identifies its id in a signaling frame it will act on the
commands received from the NCS and in case of a channel assignment message being received tune to
the assigned transmit-receive frequency pair.
The return channel is a 2.8 kBaud TDMA 3 kBaud for all service types.
WAVECOM decodes SAT-M 2.4 kbps fax, data as well as 64 kbps ISDN. The decoder will automatically ad-
just to the modulation type in use (BPSK, OQPSK or QAM16).
Additional information:
See “ SAT Settings… ” on page 45.
See “ SAT System ” on page 219.
SAT-MINI-M-C-HSD
This mode is used to monitor the return channel of SAT-MINI-M-HSD transmissions.
Parameter Value
Frequency range C-Band
Operation modes Inm-mM (Return Msg Chnl)
Modulation QAM16
Symbol rate 33600 Bd
Required SNR > 20 dB (25 dB recommended)
Input format(s) IF
Unlike the other SAT modes, this mode does not automatically select a frequency. The user has to manu-
ally set the frequency and offset to the desired signal, which will then not be interfered with or changed by
the decoder (mode). The signal level should be at least 20 dB over the noise, a 25 dB level will deliver
good results.
Session start and end are automatically recognized, but if the signal is too weak, meaningful sessions will
not be decoded and consequently a session file will not be generated, even if some intermediate decoding
has occurred.
The following services are decoded:
 ISDN
Operation