Wavecom W-SPECTRA (Automatic Monitoring System) V1.1.0 - Manual (Page 68)

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Transmission Modes WAVECOM Monitoring System W-SPECTRA, W-SPEED Manual V1.1.0
Parameter Value
Frequency range HF
Operation modes ALE, Broadcast/Simplex FEC
Modulation MFSK-8
Symbol rate 50 Bd
Center frequency 1625 Hz
Receiver settings DATA, CW, LSB or USB
Input format(s) AF, IF
ALF-RDS
ALF-RDS (Accurate positioning by Low Frequencies) is a German system for the transmission of DGPS in-
formation on low frequencies (in this case 123, 7 kHz). Data is transmitted in RDS format. RDS (Radio Da-
ta System) is a one-way data transmission system used by FM broadcasters worldwide to broadcast pro-
gram, time and traffic information on a 57 kHz BPSK DSB sub carrier with suppressed carrier and a bit
rate of 1187.5 bps. In the case of ALF-RDS, the transmission is made in SSB with a decreased level pilot
carrier to reduce bandwidth.
Parameter Value
Frequency range HF
Operation modes Broadcast FEC
Modulation BPSK
Symbol rate 1187.5 Bd
Receiver settings DATA, CW, LSB or USB
Input format(s) AF, IF
The basic RDS data unit is a group which consists of four blocks, each having 16 data bits and 10 error
detection and correction bits. Groups are divided into type A and B, each containing 16 different groups.
In the upper window, a Display Mode can be selected. The default display mode is All Blocks, which dis-
plays the information of each block. Binary will display the contents of a group in binary format.
In the lower window, other information like flags, time, program information and transmitted text is dis-
played.
ALIS
ALIS (Automatic Link Set-up) is a simplex ARQ system and operates at a Symbol rate of 228.66 Baud on
the radio link.
ALIS is described in report 551-2 of the ITU "Reports of the CCIR 1990 - Fixed Services at Frequencies be-
low about 30 MHz".