Advantech L-Band Satellite Modulator, Installation And Operation Manual

Page: 29 / 90

Installation
Note
The DVB system can be configured to transmit both MPEG-2 and non MPEG-2 data. When using
DVB modes to transmit non MPEG-2 data it is necessary to turn DVB REMOVE MARK ON in the
modulator (command
RRMVMK
ON). This is required, since DVB FEC utilizes the MPEG framing
structure, which must therefore be imposed by the modulator (and similarly removed by the
modulator). There is a performance overhead associated with the sync byte, but it is only 0.5% of data
rate.
Table 2.14: FEC/Mode/Rate Configuration Values
Mode Modulation Rates
Intelsat 308/309 BPSK, QPSK
OQPSK Rates:
½, ¾ and 7/8 are valid along with
the option of Reed-Solomon OFF/
219 or 126
Intelsat 310 8PSK Rates:
2/3 and again with the option of
Reed-Solomon OFF/ 219 or 126
DVB-S QPSK
OQPSK
Rates:
½, 2/3, ¾, 5/6 and 7/8
DVB-DSNG 8PSK and 16QAM Rates
2/3, 5/6 8/9 in 8PSK and ¾ and
7/8 in 16QAM.
DVB-S2S QPSK, 8PSK, 16APSK, 32APSK Rates
¼, 1/2. 3/5 2/3, ¾, 4/5, 5/6, 8/9
DVB-S2N QPSK, 8PSK, 16APSK, 32APSK Rates
1/2. 3/5 2/3, ¾, 4/5, 5/6, 8/9, 9/10,
1/4
TPC4K BPSK,QPSK, oQPSK, 8PSK and
16QAM Rate 4/5 and 3/4
TPC16K BPSK,QPSK, oQPSK, 8PSK and
16QAM Rate 2/5, 3/5, 8/9, 7/8 and 19/20.
OM73 BPSK, oQPSK and QPSK
and NONE NONE, 1/2 and 3/4
2.7.3
Pilots Insertion
To aid carrier recovery and a physical layer framing synchronization, the DVB-S2 standards
proposes optional insertion of pilot symbols. The system provides a regular physical layer framing
structure, based on SLOTs of M = 90 modulated symbols, allowing reliable receiver
synchronization on the FEC block structure. A slot is devoted to physical layer signalling,
including Start-of-Frame delimitation and transmission mode definition. This mechanism is
suitable also for VCM and ACM demodulator setting. Carrier recovery in the receivers may be
facilitated by the introduction of a regular raster of pilot symbols (P = 36 pilot symbols every 16
SLOTs of 90 symbols), while a pilot-less transmission mode is also available, offering an additional
2,4 % useful capacity. The pilot presence/absence in VCM and ACM can be changed on a
frame-by-frame basis.
SBD75e Series Modulator Installation and Operation Manual
2-15