On 28-Sept, you wrote
>Poor phase noise produces frequent cycle slips: the carrier tracker looses
>a cycle and delays or advances itself PI/2 (for QPSK). In an uncoded
>transmission, this procudes few errors, but the effect is terrible for
FEC,
........
The phase noise problem is critical only for low symbol rate transmissions
(3 Msymbols/s or under). For Direct-To-Home transmission, the symbol
rate used is within 20-30 Msymbols/s.
Even with the poor consumer front-end (phase noise of -70dBc at
10 kHz offset), we have never seen cycle slip with our DVB services (27.5
Msymbols/s)
Nghia PHAM
Digital System Engineer
EUTELSAT- Paris
Fax:33 1 53 98 47 98
Tel: 33 1 53 98 47 21
This archive was generated by hypermail 2b29 : Mon Feb 14 2000 - 16:14:47 EST